The killing of Iranian nuclear scientists in U.S.-Israeli military strikes has raised fears that, if the regime destabilizes, weakened control over uranium stockpiles and the spread of nuclear expertise could increase proliferation risks.

While Iran can replace its lost personnel, experts say the lost expertise will be harder to rebuild and undisclosed sites in the country may also leave dangerous materials and knowledge vulnerable.

«Currently, the risk of nuclear terrorism or nuclear material moving to the black market remains low,» said Kelsey Davenport, director of nonproliferation policy at the Arms Control Association.

«Non-state actors would face challenges in accessing enriched uranium, and it is unlikely they would have the infrastructure to enrich it to weapons-grade levels and convert it into the metallic form required for a warhead core,» she said.

UN NUCLEAR CHIEF WARNS STRIKE NEAR IRAN REACTOR RISKS CROSSING ‘REDDEST LINE’

«However, if the current Iranian government implodes or the conflict causes significant internal instability, there is an increased risk that nuclear materials will be stolen or diverted to undeclared sites.»

«There is also a risk that Iranian nuclear scientists may be willing to sell their expertise to states or non-state actors seeking nuclear weapons,» Davenport said in a new report.

Several senior figures in Iran’s nuclear and defense infrastructure have been killed over the past two years, coinciding with the campaign of U.S. and Israeli strikes on Iran’s nuclear facilities between 2025 and 2026.

Among them is Hossein Jabal Amelian, head of the Organization of Defensive Innovation and Research (SPND), who was killed in 2026 during Operation Rising Lion and Operation Epic Fury.

ISRAELI MINISTER OUTLINES IRAN MISSION GOALS, SAYS IRANIAN PEOPLE NOW HAVE CHANCE TO ‘REGAIN THEIR FREEDOM’

President Pezeshkian said Iran would rebuild the nuclear facilities targeted by the U.S., and make them stronger in 2025. (Iranian Presidency/Handout/Anadolu via Getty Images)

SPND is seen as the successor to Iran’s pre-2004 nuclear weapons program and plays a key role in new weaponization research.

Others killed in 2025 include Mohammad Mehdi Tehranchi, Akbar Motallebizadeh and Said Borji, all linked to weaponization work.

«The full impact of this campaign on Iran’s weaponization capabilities remains unclear,» Jim Lamson, a senior research associate at the Center for Nonproliferation Studies, told Fox News Digital.

«There will be replacements of the managers and scientists, but the impact on the killed officials’ experience and expertise will be hard to replace,» the former CIA analyst said.

«Many key scientists involved in suspected weaponization work were killed in 2025 and 2026.»

«Their successors may also fear being targeted in the future, whether by military strikes or assassination. That could affect their motivation and willingness to participate in any nuclear weapons program.»

AFTER THE STRIKES, HOW WOULD THE US SECURE IRAN’S ENRICHED URANIUM?

Mourners carry the coffin of Iranian nuclear scientist Mohammad Reza Sedighi Saber. (Alborz Irani/SOPA Images/LightRocket via Getty Images)

Lamson also said many of those targeted were embedded in sensitive areas of Iran’s nuclear work, including the fuel cycle and weaponization.

«These scientists had expertise in areas of the nuclear fuel cycle of key concern for nuclear weapons, including the production of highly enriched uranium (HEU), which was Iran’s main pathway for fissile material,» he said.

«The scientists also had expertise in weaponization — that is, in key aspects of the design and production of nuclear explosive devices,» Lamson added.

That said, U.S. and Israeli targeted strikes have also hit a network of sites tied to their work, creating extra obstacles for Iran’s program in the near term, he said.

«We have identified at least 11 weaponization-related sites that have been hit since 2024,» Lamson said.

«These include SPND headquarters, a newly identified site called Min-Zadayi in northeast Tehran, SPND’s Taleghan and Sanjarian explosives testing sites, the Defense Ministry’s Shahid Meisami complex in western Tehran and several research universities.»

These facilities were all involved in neutronics, explosives, metallurgy and nuclear physics — all tied to nuclear weapons development, he said.

TRUMP’S MIDDLE EAST ENVOY REVEALS WHAT LED TO BREAKDOWN IN IRAN TALKS BEFORE OPERATION EPIC FURY

Satellite imagery shows reinforcement efforts at Pickaxe Mountain site as Trump says Tehran is pursuing nuclear weapons. (Vantor/Reuters)

Despite the scale of the latest strikes, Iran retains enriched nuclear material, with President Donald Trump saying April 17 that the U.S. would work with Iran to recover «nuclear dust» — enriched uranium — from sites, adding that both countries would use heavy machinery to remove it.

The International Atomic Energy Agency also estimates Iran still holds more than 200 kilograms of uranium enriched to 60% at Esfahan—enough for roughly five weapons if further enriched.

Iranian Foreign Minister Seyed Abbas Araghchi also said it remains «under the rubble» of previous strikes and that Tehran has no plans to recover it.

«It is always possible that Iran has additional sites that were not known to Israel and the U.S.,» Lamson said.

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«We will have to wait to see how much these operations translate into a lasting strategic impact on Iran’s ability to produce nuclear weapons.»

«It’s easier to identify the damage and death caused by the Israeli and U.S. strikes, and harder to assess their actual impact on Iran’s capabilities and intentions to produce a nuclear weapon,» Lamson clarified.

En 1944, mientras el continente europeo vivía con incertidumbre vísperas del desembarco aliado, el autor Graham Greene comunicó su dimisión del MI6 a su jefe Kim Philby en el Café Royal de Regent Street en Londres. Este movimiento inesperado, ocurrido en pleno desarrollo de la Operación Overlord, marcó un punto de inflexión en la colaboración entre el escritor británico y el hombre que, desde el corazón del espionaje inglés, operaba secretamente al servicio de Moscú, y que se recupera en The Writer and the Traitor: Graham Greene, Kim Philby and the Great Betrayal de Robert Verkaik.

Un dato que distingue este episodio es que la renuncia de Greene ocurrió antes de que la traición de Philby fuera reconocida por las autoridades británicas. No sería hasta dos décadas después, en 1963, cuando los servicios de inteligencia del Reino Unido confirmaron la doble vida de Philby, quien finalmente desertó a la Unión Soviética y pasó sus últimos años en Moscú, alejado del ideal revolucionario que lo guiaba en juventud y obsesionado con detalles de la vida inglesa, como recibir mermelada y resultados de críquet.

Durante aquel almuerzo en el Café Royal, mientras la ciudad se preparaba para el Día D, Greene notificó a Philby —entonces jefe de la Sección V de contraespionaje— su decisión de abandonar el MI6. La escena no solo marcó el final de la colaboración entre ambos, sino que también levantó una incógnita persistente: Greene, descrito como un “sociólogo del pecado” por Verkaik, ¿captó señales de traición en su interlocutor en ese momento crucial?

Verkaik, autor de un reciente retrato dual sobre ambos personajes, plantea la pregunta pero rehúsa ofrecer una respuesta definitiva. Greene ya arrastraba desde la infancia un sentido de lealtades divididas entre la autoridad de su padre, director de la escuela de Berkhamsted, y el rechazo de sus compañeros. Su vida adulta se caracterizó por el riesgo y la identificación con causas dispares, frecuentando ambientes marginales de Londres durante el Blitz y recabando experiencias que más tarde alimentarían su literatura y su trabajo en inteligencia.

Kim Philby aparece esbozado por Verkaik como el prototipo de “clase dirigente británica”, aunque matiza que su entorno social siempre estuvo en la periferia de ese universo. Hijo de St John Philby, asesor del rey saudita y converso al islam, Kim se incorporó al MI6 amparado por la aparente garantía de que su militancia comunista era una fase juvenil. Sin ser un miembro pleno de la elite británica, el resentimiento y su experiencia universitaria habrían fortalecido su inclinación revolucionaria.

La frialdad de Philby contrastaba con la actitud performativa de Greene. Philby, cuyo primer idioma fue el punjabi debido a su nacimiento en la India, mantenía una vida sentimental turbulenta: cuatro matrimonios y múltiples aventuras, organizando la traición y la vida privada con igual aplomo.

Como señala Verkaik, Philby no solo traicionaba entregando detalles operativos y análisis estratégicos a Moscú, sino que también transmitió información esencial sobre el desembarco aliado. Su apuesta era que Stalin no traicionaría a los aliados occidentales. De haber procedido de otra manera el Kremlin, la costa de Normandía podría haberse convertido en una zona de masacre para las fuerzas aliadas.

Durante años, la naturaleza sospechosa de la renuncia de Greene permaneció abierta a la interpretación: ¿fue un acto motivado por el desengaño burocrático o por la percepción de la doble vida de Philby? Lo cierto es que la confirmación oficial del espionaje de Philby demoró dos décadas, hasta su huida y asilo en la Unión Soviética.

En Moscú, lejos de la vida opulenta o idealizada del agente mítico, Philby vivió reclamando pequeños recuerdos de Inglaterra. Los informes destacan que enviaba mensajes a sus contactos solicitando “mermelada inglesa y los últimos resultados del críquet”, mostrando un contraste irónico entre la trascendencia política de su traición y la trivialidad cotidiana de su exilio final.

Hundreds of commercial tankers are stranded on both sides of the Strait of Hormuz after Iran shut the critical chokepoint on April 18, halting traffic and leaving crews trapped amid reports of gunfire and «traumatic experiences» on board.

The Strait of Hormuz is considered an international waterway under international law, through which ships have the right of transit passage, according to the United Nations Convention on the Law of the Sea (UNCLOS).

Roughly one-fifth of the world’s oil supply passes through the Strait of Hormuz, making it a critical chokepoint for global energy markets, according to the U.S. Energy Information Administration.

The U.K. Maritime Trade Operations (UKMTO) said Iranian gunboats opened fire on a tanker the same day, while a projectile struck a container vessel, damaging cargo.

STARMER AND MACRON ACCUSED OF ‘PLAYING AT BEING RELEVANT’ WITH STRAIT OF HORMUZ PLAN

Audio released by maritime monitoring group TankerTrackers appears to capture the moment a vessel and its crew came under fire while approaching the strait, including a distress call from a crew member.

«Sepah Navy! Motor tanker Sanmar Herald! You gave me clearance to go… you are firing now. Let me turn back!» the crew member can be heard saying in the recording, according to TankerTrackers.

Iranian state media confirmed that shots were fired near vessels to force them to turn back, while the Ministry of External Affairs of the Government of India said the foreign secretary was deeply concerned.

Hapag-Lloyd, the world’s fifth-largest container shipping line, told Fox News Digital that it had activated a crisis team as its crews remain stuck on board vessels in the region.

«We have been working from Friday afternoon until today with the entire crisis team to bring the vessels out — in vain, unfortunately,» said Nils Haupt, senior director of group communications at Hapag-Lloyd AG.

«These events can easily lead to traumatic experiences. There is also a significant risk from sea mines, which has made insuring vessels for passage through the Strait nearly impossible.»

LISA DAFTARI: HORMUZ WHIPLASH PROVES TEHRAN CAN’T HONOR ANY DEAL IT SIGNS

«The crews are well, but they are becoming increasingly impatient and frustrated. It is very unfortunate that we could not leave today,» he added. «Many ships are still stuck in the Persian Gulf.»

«Our six ships are anchored near the port of Dubai, and all crews hope for an improvement in the situation,» Haupt said.

The Islamic Revolutionary Guard Corps (IRGC) said on April 18 that the strait would remain closed until the U.S. lifts its blockade on Iranian ports, warning ships not to move from anchorage or risk being treated as «enemy» collaborators.

Iran has previously argued that restrictions on its oil exports and shipping amount to «economic warfare,» framing actions in the Strait of Hormuz as a response to foreign pressure on its economy, according to statements from Iranian officials and state media in past incidents.

«Approaching the Strait of Hormuz will be considered cooperation with the enemy, and any violating vessel will be targeted,» the IRGC said in a statement carried by the semi-official Tasnim News Agency.

TRUMP ORDERS A BLOCKADE IN THE STRAIT OF HORMUZ AS TENSIONS WITH IRAN SOAR

Fishing boats dot the sea as cargo ships, in the background, sail through the Arabian Gulf toward the Strait of Hormuz off the United Arab Emirates, Friday, March 27, 2026. (AP Photo)

The United States imposed the blockade on Iranian ports to pressure Tehran to reopen the strait, with U.S. Central Command saying the measures are being enforced «impartially against all vessels.»

Hapag-Lloyd said its vessels have been stuck for weeks following the initial closure after the outbreak of war with Iran on Feb. 28.

«For us, it is critical that our vessels can pass through the strait soon,» Haupt said.

«We offer all crew members unlimited data so they can video call loved ones and access entertainment. Crews are strong, but after weeks on board there is growing monotony and frustration.»

«One crew experienced a fire on board from bomb fragments. Others have seen missiles or drones near their vessels,» he added.

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«They are resilient, but each additional day makes the situation more difficult, more monotonous, and more stressful.»

President Donald Trump said Iran had agreed not to close the strait again but after the closure, Trump called the situation «blackmail» and said the U.S. would not back down.