Iran’s Top Nuclear Scientist, Mohsen Fakhrizadeh, Killed in Attack: Live Updates - The New York Times

and Israeli intelligence assessments as the force behind Iran’s nuclear weapons program.

Three intelligence officials said that Israel was behind the attack.

Iran’s top nuclear scientist, who American and Israeli intelligence have long charged was behind secret programs to design an atomic warhead, was shot and killed on Friday as he was traveling in a vehicle in northern Iran, Iranian state media reported.

The scientist, Mohsen Fakhrizadeh, believed to be 59, has been considered the driving force behind Iran’s nuclear weapons program for two decades, and continued to work after the main part of the effort was quietly disbanded in the early 2000s, according to American intelligence assessments and Iranian nuclear documents stolen by Israel.

Three intelligence officials said that Israel was behind the attack on the scientist.

Fakhrizadeh was shot as his car was driving through the countryside town of Absard, in the Damavand region, according to official Iranian media and state television.The state media accounts said that Mr.

“He was their senior-most nuclear scientist and was believed to be responsible for Iran’s covert nuclear program,” Mr.

In 2008, his name was added to a list of Iranian officials whose assets were ordered frozen by the United States.

But an Israeli operation in early 2018 that stole a warehouse full of Iranian documents about “Project Amad,” what the Iranians called the nuclear weapons effort 20 years ago, included documents about Mr.

Israeli officials, later backed up by American intelligence officials who reviewed the archive, said the scientist had kept elements of the program alive even after it was ostensibly abandoned.

3 that killed Qassim Suleimani, the Iranian major general who ran the elite Quds force of the Islamic Revolutionary Guards Corps.

to revive the 2015 Iranian nuclear deal, as he has pledged to do, if the Iranians agree to return to the limits detailed in the accord.

President Trump withdrew the United States from the Iran nuclear deal in 2018, unraveling the signature foreign policy achievement of his predecessor, Barack Obama, and isolating the United States from Western allies who tried to keep the agreement intact.

Israel has long opposed the nuclear deal, and if its agents were responsible for the killing of a man considered a national hero — in Iran, they will almost certainly be accused of being behind it — there could be political pressure in Iran to move forward with its current effort to gradually rebuild the stockpile of nuclear fuel that it gave up in 2015.

But some American officials argued that the death of Mr.

Fakhrizadeh comes just two weeks after intelligence officials confirmed that Al Qaeda’s second-highest leader was gunned down on the streets of Tehran by Israeli assassins on a motorcycle on Aug.

Attacking Iran to force it to stop expanding its nuclear program would be a significant blow to Mr.

Esper, and other top Pentagon aides last week, Defense Department and other national security officials have privately expressed worries that the president might initiate operations, whether overt or secret, against Iran or other adversaries at the end of his term.

Milley, the chairman of the Joint Chiefs of Staff — argued against a military strike against Iran, top American officials and commanders still warn of Iran’s malign activities