Iran expressed fury over the killing of Mohsen Fakhrizadeh, blaming it on Israel and the United States. His death may complicate President-elect Biden’s intention to restore the Iranian nuclear deal.
Iran’s top nuclear scientist, long identified by American and Israeli intelligence as the guiding figure behind a covert effort to design an atomic warhead, was shot and killed Friday in what the Iranian media called a roadside ambush as he and his bodyguards traveled outside Tehran.
For two decades, the scientist, Mohsen Fakhrizadeh, was the driving force behind what American and Israeli officials describe as Iran’s secretive nuclear weapons program. His work continued after Iran’s push to develop a bomb was formally disbanded in 2003, according to American intelligence assessments and Iranian nuclear documents stolen by Israel nearly three years ago.
Iranian officials, who have always maintained that their nuclear ambitions are for peaceful purposes, not weapons, expressed fury and vowed revenge over the assassination, calling it an act of terrorism and warmongering that they quickly blamed on Israeli assassins and the United States.
The White House, C.I.A. and Israeli officials declined to comment. But Mr. Fakhrizadeh’s assassination — only 10 months after the United States killed the powerful spymaster at the head of Iran’s security machinery in a drone attack in Iraq — could greatly complicate President-elect Joseph R. Biden Jr.’s plans to reactivate the 2015 nuclear agreement between Tehran and six other nations, which curtailed Iran’s nuclear activities.
The assassination of Mr. Fakhrizadeh had the hallmarks of a precisely timed operation. The Iranian state news media said that gunmen waited along the road and attacked as his car was driving through the countryside town of Absard, an area known as a bucolic escape with majestic mountains about 40 miles east of Tehran.
“Terrorists murdered an eminent Iranian scientist today,” Iran’s foreign minister, Mohammad Javad Zarif, wrote on Twitter. “This cowardice — with serious indications of Israeli role — shows desperate warmongering of perpetrators.”
Mr. Zarif, who negotiated the Iran nuclear deal and remains one of Iran’s most recognizable figures, said in the post that the international community should “end their shameful double standards & condemn this act of state terror.”
On Friday night, Iran sent a letter to U.N. Secretary General Antonio Guterres, condemning what it called “a terrorist attack” and warning that the country “reserves its rights to take all necessary measures to defend its people and secure its interests.”
John Brennan, who was the C.I.A. director under Mr. Obama, called the killing “a criminal act & highly reckless” in a tweet. “It risks lethal retaliation & a new round of regional conflict,’’ he wrote, urging Iran to “wait for the return of responsible American leadership” and resist temptations to strike back.
The Pentagon’s former top Middle East policy official, Michael P. Mulroy, said Mr. Fakhrizadeh’s death was “a setback to Iran’s nuclear program.” He noted that the scientist “was also a senior officer in the Islamic Revolutionary Guards Corps, and that will magnify Iran’s desire to respond by force.”
It also remains unclear how much the killing will set back the Iranian program. Mr. Fakhrizadeh had the background and oversight to understand the challenges of physics and politics the Iran nuclear program faced. But Iran recovered from the assassinations of lower-level scientists, and from the cyberattacks from 2007 to 2010 on the nuclear fuel production site at Natanz, a joint Israeli-American operation code-named “Olympic Games.”That operation set Iran back by a year or so.
The killing 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. 7, at the behest of the United States.
The assassination comes at a time of greatly heightened tensions between Iran and the Trump administration. Mr. Trump was dissuaded from striking Iran just two weeks ago, after his aides warned that it could escalate into a broader conflict during his last weeks in office.
Mr. Trump had asked senior advisers in an Oval Office meeting on Nov. 12 whether he had options to take action against Iran’s main nuclear site at Natanz in the coming weeks. Days later, Mr. Pompeo visited Israel on what could be his last trip there in office.