Iran’s state media announced on Wednesday that 15 people, including Iranians and unspecified foreigners, had been arrested in connection with what the country’s Intelligence Ministry described as a “Zionist- regime-linked” plot to assassinate one of its “specialists.” The report by the state broadcaster IRIB also said Iran’s intelligence services had uncovered an Israeli spy base in a neighboring country, without elaborating.

While providing few specifics, the new details of the arrests, which were first announced last week, appeared to link the alleged plot with the killing of scientists from Iran’s disputed nuclear program. At least five have died under mysterious circumstances since 2007, including Mostafa Ahmadi Roshan, the deputy director at the Natanz enrichment site, who was killed in January by a magnetic bomb attached to his car by an unidentified motorcyclist.

The report came a day after Iran said it had appointed one of its top nuclear scientists — and the target of an assassination attempt in November 2010, also by a motorcyclist with a magnetized bomb — to a new post as the commander for nuclear and radioactive emergencies. The new duties assumed by the scientist, Fereydoon Abbasi, were not clear from the announcement.

Iranian leaders have blamed Israel and the United States for the killings of its scientists, a charge categorically denied by the United States. Israel, which considers Iran its most dangerous enemy, has been more vague. Both countries suspect Iran of seeking to develop the capability to make nuclear weapons, but Iran has insisted its program is for peaceful purposes.

After the January assassination, President Mahmoud Ahmadinejad of Iran ordered new security measures for its nuclear scientists, and Iranian lawmakers said at the time that several suspects had been identified in the killing.

The timing of the arrests described on Wednesday was not immediately clear. The official Islamic Republic News Agency reported on April 10 that all the members of a “terrorist team” had been detained by security forces in Iran before they had a chance to carry out their attack. The report promised further details in the coming days.

In describing the alleged plot on Wednesday, the new report said that the attack had been planned for Feb. 10, a day ahead of anniversary celebrations observing Iran’s 1979 revolution, appearing to indicate that the arrests may have taken place more than two months ago.

The report also said intelligence services had discovered “a Zionist regime’s spy base” in an unspecified neighboring country, and said that it was “run by the Mossad spy agency to carry out operations against the interests of Iran,” referring to Israel’s intelligence agency. (Copyright 2012 The New York Times Company 04/19/12)