Iran has made arrests in connection with the assassination last week of a top nuclear scientist. Tehran has blamed Israel and the United States for the death of Ahmadi Roshan, a chemist and deputy director of Iran's main Natanz uranium enrichment plant.

Parliamentary speaker Ali Larijani said on Monday that investigators had discovered clues and made an unspecified number of arrests. He also gave no details on the suspects' identities or nationalities.

"We have discovered some clues and some arrests have been made. Investigations are ongoing," Larijani told Iran's Arabic-language broadcaster Al-Alam.

He said the suspects were being interrogated. He also vowed that Iran would avenge Roshan's death. The killing was the fifth such attack targeting Iranian scientists in the last two years. Four of the victims died and one managed to escape.

Iran vows to 'punish those responsible'

The United States has strongly denied any role in the murders and Israel has refused to comment in line with its policy on intelligence matters.

On Saturday, the deputy chief of Iran's joint armed forces, Masoud Jazayeri, said Tehran would "punish those responsible" and was considering a response to hold the US, Israel and Britain "accountable" for their perceived involvement in the attacks.

Iran's supreme leader, Ayatollah Ali Khamenei, on Thursday blamed the US and Israeli intelligence services for the latest killing. He said that Iran would "continue with determination" its nuclear activities, which Western countries suspect are aimed at developing nuclear weapons, despite Iranian denials.

Author: Gregg Benzow (AP, AFP)
Editor: Michael Lawton