Iran's English-language Press TV said on Monday that the weapon used in the killing of a prominent Iranian nuclear scientist last week was made in Israel.
"The weapon collected from the site of the terrorist act (where Mohsen Fakhrizadeh was assassinated) bears the logo and specifications of the Israeli military industry," an unnamed source told Press TV.
Speaking before the Press TV report, Israeli intelligence minister Eli Cohen told radio station 103 FM on Monday that he did not know who was responsible.
Fakhrizadeh, who had little public profile in Iran but had been named by Israel as a prime player in what it says is Iran's nuclear weapons quest, was killed on Friday when he was ambushed on a highway near Tehran and his car sprayed with bullets.
Iran began Fakhrizadeh's burial in a cemetery in northern Tehran on Monday, state TV reported, as the defence minister promised that the Islamic Republic would retaliate for his killing.
Iran's clerical and military rulers have blamed Iran's longtime enemy, Israel, for Fakhrizadeh's killing, raising the threat of a new confrontation with the West and Israel in the remaining weeks of Donald Trump's presidency.
However, Iran's rulers are aware of daunting military and political difficulties in attacking Israel. Such an attack would also complicate any effort by U.S. President-elect Joe Biden to revive detente with Tehran after he takes office on Jan. 20.
Tensions have increased between Tehran and Washington since 2018, when Trump exited Iran's 2015 nuclear deal with six powers and reimposed sanctions that have crippled Iran's economy.
In retaliation, Tehran gradually breached the deal's curbs on its nuclear programme. Biden has said he will return the United States to the deal if Iran resumes compliance.
Tehran has always denied seeking nuclear weapons.