(Image source: Fars News)

BY ZACH TOOMBS

Iran’s state news agency blamed the CIA and Britain’s MI6 for this week’s assassination of an Iranian nuclear scientist.

Reported Saturday in The Jerusalem Post:

“(The letter states) CIA-led operations in the Islamic Republic are known... blaming the US for supporting ‘terrorist groups against Iran.’ Tehran also sent a letter to the British Foreign Office, claiming British intelligence aided in the killing of the (scientist). Iran demanded a response from both governments.”

As France 24 reports, the targeting of this scientist -- and the way he was killed -- could be signs of espionage.

“The bomb was attached to scientist Mostafa Ahmadi-Roshan's car, killing him instantly. Roshan was a scientist and a director at Iran’s uranium enrichment facility... Three other Iranian scientists were killed in the past two years when their cars blew up.”

The letter from Iran’s state news agency represents the nation’s most direct accusation yet. And, although it points the finger at the United States and the UK, Al Jazeera reports Israel’s spy agency Mossad and even some Iranian dissidents are also suspected.

“What is interesting, I think, there is obviously a network operating in Iran, and it has internal -- whether it is Israel or not -- there are Iranians inside Iran that are helping.”

Speaking to troops at Fort Bliss in El Paso, Texas, Defense Secretary Leon Panetta adamantly denied any American involvement in the killing of the Iranian nuclear scientist.

“We have some ideas as to who might be involved, but we don’t know exactly who was involved. But I can tell you one thing. The United States was not involved in that kind of effort. That’s not what the United States does.” (Video source: The Guardian)

And on CNN, a former CIA officer discredited accusations of U.S. involvement -- and said the killings were likely the work of Israel.

“I, myself, think it was some kind of dissident group, perhaps at the behest of Israel. I know it wasn’t the United States. There was no lethal finding against Iran. That kind of information would leak out, and we wouldn’t get these kind of denials that we’ve gotten out of the administration.”

Regardless of who is behind the assassination, the BBC reports the continued attacks on Iran’s scientists have had little effect on the government’s nuclear ambitions.

“Iran's supreme leader Ayatollah Ali Khamenei has vowed to punish those behind the death of Mr Ahmadi-Roshan, who worked at the Natanz uranium enrichment facility. ‘We will continue our path with strong will... and certainly we will not neglect punishing those responsible for this act...’