President Shimon Peres said he was unaware of any Israeli involvement in a deadly bombing in Tehran which killed an Iranian nuclear scientist, in an interview broadcast on Friday by CNN.
Asked by CNN's Spanish service if Israel was involved in Wednesday's car bomb attack, the veteran statesman replied: "Not to the best of my knowledge."
Iran has blamed Israel and the United States for the deadly attack which killed 32-year-old Mostafa Ahmadi Roshan along with his driver/bodyguard.
He was the fourth Iranian scientist to be killed in an explosion in the past two years, with the finger repeatedly pointed at Israel.
Israeli officials rarely respond to such accusations and for the most part, do not comment on events in Iran.
Several hours after the blast, Israel's military spokesman Brigadier General Yoav Mordechai also said he was unaware of who was behind the bombing which he described as an act of "revenge."
"I don't know who took revenge on the Iranian scientist, but I am definitely not shedding a tear," Mordechai wrote on his official Facebook page.