Iran's intelligence minister accused the U.N. nuclear watchdog agency of sending spies in the guise of inspectors to collect information about Iran's nuclear activities, state TV reported Saturday.

The claim was another sign that Iran has hardened its stance since the assassination a week ago of a prominent nuclear scientist and the wounding of another. Iran is to hold talks beginning Monday in Geneva with world powers trying to persuade it to curtail key elements of its nuclear work.

Intelligence Minister Heidar Moslehi said that inspectors sent by the International Atomic Energy Agency had engaged in espionage and the Vienna-based agency must take responsibility for their actions. He did not elaborate or identify the inspectors Iran was accusing.

Iran has increasingly alleged in recent months that the agency's inspectors have leaked information to U.S. officials and other allies. In June, Iran banned two U.N. nuclear inspectors from entering the country, claiming they had leaked "false" information about the country's disputed nuclear program.