Iran says it has arrested suspects in the assassination of a nuclear scientist one year ago.
Iran's state television read a secret service statement Monday saying the suspects formed a "network of spies and terrorists" linked to Israel's Mossad intelligence service. It also claimed Iran's security forces had infiltrated the Israeli spy agency.
Iran blamed the United States and Israel for the murder last year of nuclear physics professor Massoud Ali-Mohammadi. He was killed outside his home in northern Tehran on January 12 when a remote-controlled bomb exploded on a motorbike.
U.S. officials have called the accusation of involvement absurd. Israeli Cabinet Minister Benjamin Ben Eliezer said last year it was not surprising that Iran blamed Israel, but he said he knew nothing about the incident.
Iran also has blamed Israel and Western nations for a pair of bomb attacks that killed one nuclear scientist, Majid Shahriari, and wounded another, Fereydoon Abbasi-Davani, in Tehran in November.
A number of governments believe Iran is using its civilian nuclear program as a cover to develop nuclear weapons - a charge Iran denies.
The United Nations Security Council has imposed four sets of sanctions on Iran for its refusal to stop enriching uranium.