Iran’s President Hassan Rouhani on Monday claimed that Israel was behind the killing of a scientist who founded the Islamic Republic’s military nuclear program in the 2000s in an effort to start a war in the last days of President Trump’s administration.

Rouhani’s comments in a news conference marked the first time he has directly accused the Jewish state of carrying out the killing of Mohsen Fakhrizadeh late last month.

Israel, long suspected of killing Iranian nuclear scientists over the last decade, has repeatedly declined to comment on the attack.

“Waging instability and war in the final days of the Trump administration was the main aim of the Zionist regime in the assassination,” Rouhani said.

Rouhani vowed to avenge the killing but said his country will not allow Israel to decide the “time or venue“ of any retaliatory action. He said Iran will not allow instability in the region.

Fakhrizadeh headed Iran’s so-called AMAD program, which Israel and the West have alleged was a military operation looking at the feasibility of building a nuclear weapon. The International Atomic Energy Agency says that the “structured program” ended in 2003. U.S. intelligence agencies concurred with that assessment in a 2007 report.

After the killing of Fakhrizadeh , a top Iranian security official, Ali Shamkhani, accused Israel of using “electronic devices” to remotely kill the scientist.

Israel insists Iran still maintains the ambition of developing nuclear weapons, pointing to Tehran’s ballistic missile program and research into other technologies. Iran long has maintained that its nuclear program is for peaceful purposes.

(AP)