Mr Perry told reporters in Jerusalem that the US was "very much concerned about the potential that Iran might become a nuclear power. I don't care to make a comment on that until I have read the detailed analysis of that report," he said, referring to the $800m (£515m) construction deal signed by Iran and Russia yesterday. "We do not consider that an acceptable development.
Two German firms began work on the Bushehr plant in 1974, before the overthrow of the Shah. The project was later halted and the plant was heavily damaged by bombing raids during the Iran-Iraq war.
"The Iranian side entered into an accord with Russia worth $800m to complete the project and Moscow agreed to complete the first unit of the nuclear power plant within four years," the plant's acting director, Kazem Khabir, said.
In a two-hour meeting with the Israeli Prime Minister, Yitzhak Rabin, Mr Perry said the US wanted "a nuclear non-proliferation regime applied to the whole area", but he did not specifically request that Israel join the Nuclear Non-Proliferation Treaty, the official said.
Iran in turn yesterday warned of an Israeli "atomic threat" and urged Middle Eastern countries to press Israel to destroy its nuclear arsenal, the official Iranian news agency (IRNA) said.
"We demand all the countries of the region to take Israel's atomic threat seriously and guide their diplomacy in the direction of pressuring the Zionist regime to destroy its nuclear weapons," Mahmud Mohammadi,a foreign ministry spokesman, said.
He accused Israel of "continuing efforts to produce nuclear weapons" and criticised its refusal to have its facilities inspected by the International Atomic Energy Agency (IAEA).
Iran expressed concern at the weekend over threats that Israel may attack its nuclear facilities. Last week the New York Times reported that Israeli officials had said the country could be forced to consider attacking Iran's nuclear reactors if it does not stop its nuclear programme.