Iranian President Hassan Rohani has accused Israel of acting as a “mercenary” for the United States in connection with the assassination of Iran’s top nuclear scientist near Tehran.

“Once again, the wicked hands of the global arrogance, with the usurper Zionist regime as the mercenary, were stained with the blood of a son of this nation,” Rohani wrote on his official website on November 28.

“The global arrogance” is a term often used by Iranian officials to refer to the United States, while “the usurper Zionist regime” is a reference to Israel.

Nuclear scientist Mohsen Fakhrizadeh was assassinated in an ambush near Tehran on November 27, in a brazen attack that threatens to escalate tensions between Iran and the United States and its close ally Israel.

The head of Iran’s nuclear agency, Ali-Akbar Salehi, vowed on November 28 that Fakhrizadeh’s killing would not impair Iran’s nuclear program.

“Fakhrizadeh’s path is now being continued even more intensively,” Salehi was quoted by Iranian media as saying.

Iran immediately blamed Israel for the assassination, while suggesting the United States also had an indirect or direct role.

The assassination occurred when a truck with explosives hidden under a load of wood blew up near a car carrying Fakhrizadeh in the town of Absard, near Tehran, Iranian state media reported. As Fakhrizadeh’s sedan stopped, at least five gunmen raked the car with rapid fire and engaged in a gunfight with the scientist’s bodyguards.

Iranian Foreign Minister Mohammad Javad Zarif claimed there were “serious indications of (an) Israeli role” in the assassination.

“Terrorists murdered an eminent Iranian scientist today. This cowardice — with serious indications of Israeli role — shows desperate warmongering of perpetrators,” Zarif wrote on Twitter.

He also called on the European Union to “end their shameful double standards and condemn this act of state terror.”

Israel declined to immediately comment on the killing of Fakhrizadeh. The Pentagon, White House, State Department, and CIA also declined to comment.

The New York Times, citing one U.S. official and two other intelligence officials, said Israel was behind the attack on the scientist, although it wasn’t clear what, if any, knowledge the United States may have had about the operation.

Israeli Prime Minister Benjamin Netanyahu named Fakhrizadeh in a 2018 presentation revealing a trove of stolen documents about Iran’s alleged covert nuclear activities, saying: “Remember that name.”

Israel has long been suspected of carrying out a series of targeted killings of Iranian nuclear scientists and other sabotage operations against Iran using operatives of the Mujahedin-e Khalq (MEK), an exiled opposition group.

The killing of Fakhrizadeh, who Western intelligence services regarded as the shadowy mastermind behind Iran’s past covert nuclear weapons program, may undermine U.S. President-elect Joe Biden’s goal of reviving diplomacy with Iran when he enters the White House in January.

Biden has said he will try to rejoin the Iran nuclear accord that Trump quit in 2018 and work with allies to strengthen its terms, if Tehran first resumes compliance.

Iranian officials said the country would retaliate for the attack on the Fakhrizadeh.

The military adviser to Supreme Leader Ayatollah Ali Khamenei vowed to “strike as thunder at the killers of this oppressed martyr.”

“In the last days of the political life of their…ally (U.S. President Donald Trump), the Zionists seek to intensify pressure on Iran and create a full-blown war,” Hossein Dehghan tweeted.

Fakhrizadeh led Iran’s so-called Amad program that Israel and the West say was a military operation assessing the feasibility of building a nuclear weapon. Tehran long has maintained its nuclear program is peaceful.

The International Atomic Energy Agency says that Amad program ended in 2003. IAEA inspectors currently monitor Iranian nuclear sites as part of Iran’s 2015 nuclear deal with world powers, which Iran has gradually breached following the U.S. withdrawal.

With reporting by AFP, AP, dpa, and Reuters.

This post was originally published on Radio Free.