Iran cites U.S. role in scientist's murder

TEHRAN, Iran -- Iran said Saturday it has evidence that the United States was behind the assassination of an Iranian nuclear scientist this week in Tehran, state media reported.

Mostafa Ahmadi Roshan was killed in a brazen daylight assassination Wednesday when two assailants on a motorcycle attached a magnetic bomb to his car in the Iranian capital. The killing bore a strong resemblance to earlier killings of scientists working on the Iranian nuclear program, and has prompted calls in Iran for retaliation against those deemed responsible.

The IRNA state news agency said Saturday that Iran's Foreign Ministry has sent a diplomatic letter to the United States saying that it has "evidence and reliable information" that the CIA provided "guidance, support and planning" to assassins "directly involved" in Roshan's killing.

The United States has denied any role in the assassination.

Iran delivered the letter to the Swiss Embassy in Tehran, which looks after U.S. interests in the country. Iran and the United States have had no diplomatic relations since the 1979 Islamic Revolution.

IRNA also reported that Iran delivered a letter to Britain accusing London of having an "obvious role" in the killing. It said that a series of assassinations began after British intelligence chief John Sawers hinted in 2010 at intelligence operations against the Islamic Republic.

British media have quoted Sawers as saying that intelligence-led operations were needed to make it more difficult for countries like Iran to develop nuclear weapons. Britain's Foreign Office has condemned the killing of civilians.

Israeli officials, in contrast, have hinted at covert campaigns against Iran without directly admitting involvement.

The U.S. and its allies fear Iran's program aims to develop nuclear weapons. Iran denies the charges, and says its nuclear program is for peaceful purposes only.