Deadly attacks on Iranian nuclear scientists are being carried out by an Iranian dissident group that is financed, trained and armed by Israel’s secret service, U.S. officials tell NBC News, confirming charges leveled by Iran’s leaders.

The group, the People’s Mujahedin of Iran, has long been designated as a terrorist group by the United States, accused of killing American servicemen and contractors in the 1970s and supporting the takeover of the U.S. Embassy in Tehran before breaking with the Iranian mullahs in 1980…

Moreover, he said, the Mossad, the Israeli secret service, is training MEK members in Israel on the use of motorcycles and small bombs. In one case, he said, Mossad agents built a replica of the home of an Iranian nuclear scientist so that the assassins could familiarize themselves with the layout prior to the attack…

Two senior U.S. officials confirmed for NBC News the MEK’s role in the assassinations, with one senior official saying, “All your inclinations are correct.” A third official would not confirm or deny the relationship, saying only, “It hasn’t been clearly confirmed yet.” All the officials denied any U.S. involvement in the assassinations.