Iranian parliament speaker Ali Larijani says that Iran has made several arrests over last week's killing of an Iranian nuclear scientist.
Larijani told Iran's Arabic-language broadcaster Al-Alam that the authorities had "discovered some clues and arrests had been made."
He said the suspects were being interrogated and that investigations were ongoing.
He did not specify how many people were arrested or when the arrests were made, or give any details on the suspects' identities or nationalities.
Mostafa Ahmadi Roshan, an official in Iran's uranium-enrichment facility at Natanz, was killed in an explosion on January 11 after attackers attached a bomb to his car in Tehran.
Iran accused the United States, Britain, and Israel of involvement.
Washington denied any role in the assassination, and London condemned the killing of civilians. Israel has not commented publicly.
compiled from agency reports