Iranian state television on Monday showed several Iranians alleged to be part of a group of 13 who "confessed" to killing four Iranian nuclear scientists after being trained by Israeli intelligence.

It said the network received orders from "Washington and London."

The television report, available online (http://www.yjc.ir/fa/news/4047313), showed the suspects speaking of how they purportedly prepared to murder the scientists, and broadcast a re-enactment of assassins on a motorbike fixing a magnetic bomb to a victim's car, while dramatic music played in the background.

It also showed images of a number of prefabricated temporary buildings in an arid area and said the site was an Israeli military camp used for their training.

The 40-minute report, which was broadcast overnight, said the 13 comprised eight men and five women, all of whom were named.

One of them was Majid Jamali Fashi, who was executed on May 15 after being found guilty of spying for Israel's Mossad spy service and playing a key role in the January 2010 murder of a top nuclear scientist in return for payment of $120,000.

Iran's intelligence service recently said it had broken a ring of other "spies" linked to the scientists' slayings, which it blamed on Israel and the United States.

The United States vehemently denied any involvement in the most recent assassination, on January 11 this year. Israel has refused to confirm or deny involvement in any of the killings.

One of the suspects presented on state television, identified as Maziar Ebrahimi, told the camera that he had been "sent to Israel to learn to handle explosives, and receive other military training, including firing weapons."

Another, identified as Behzad Abdoli, said: "We went to Turkey and we took a boat from there... to go to Cyprus, and from there to Israel, to a small town near Tel Aviv."

A third, identified as Arash Kheradkish, said: "We were trained to attach timed magnetic bombs on moving cars and to get away quickly."

State television did not show any evidence to support the allegations, beyond the interviews given by the sombre looking suspects.

Detainees held by Iranian authorities have given coerced public statements in the past, notably in the case of Maziar Bahari, a Newsweek magazine journalist who was jailed for five months in 2009 and later wrote a book about his ordeal and the interview he was forced to give to Iranian television.

In December, state television showed a joint US-Iranian national, Amir Mirzai Hekmati, a former US Marine, saying in an interview that he was a CIA agent sent to infiltrate the Iranian intelligence service. His family in the United States denied he was a spy.