A top advisor to Iran's Supreme Leader has warned that those responsible for killing one of the country's top nuclear scientists would face a "calculated and decisive" response.
Tehran blames Israel for the attack.
David Doyle reports.
Iran held a ceremony to mourn prominent nuclear scientist Mohsen Fakhrizadeh on Sunday (November 29) days after his killing which Tehran blames on Israel.
Fakhrizadeh, long suspected by Western and Israeli governments of masterminding a secret nuclear weapons program, was ambushed on a highway near Tehran on Friday (November 27) and gunned down in his car.
Kamal Kharrazi, a top advisor to Iran's Supreme Leader, said in a statement on Sunday that those responsible would receive a "calculated and decisive answer" while one hardline Iranian newspaper called for an attack on the port city Haifa if an Israeli role is proven.
Iran has in the past accused Israel of killing several nuclear scientists since 2010.
Israeli Prime Minister Benjamin Netanyahu's office has declined to comment.
But Iran's rulers are aware of the daunting military and political difficulties in attacking Israel not least that it would complicate the easing of hostilities with the United States.
Iran has gradually been breaching a 2015 nuclear deal with major world powers since President Donald Trump withdrew the US.
President-elect Joe Biden has promised to return the US to the deal if Iran resumes compliance.
