Iran (search), building its first nuclear reactor and planning a second, warned Israel (searchMonday against attacking the nuclear installations as it did an Iraqi facility in 1981.

Hamid Reza Asefi (search), the Foreign Ministry spokesman, told reporters Monday that he hoped Israel, which has warned against Iran's alleged nuclear weapons program, would not resort to such an "adventure."

"At any rate, the Zionist regime proved to be adventurous in the past and doesn't abide by any principles. In case it will commit such a mistake, it will pay dearly," he said.

Israeli officials have been urging the United States and Europe to pressure Iran to stop its alleged nuclear weapons programs after Tehran (search) inaugurated a missile capable of hitting Israel.

Analysts have speculated that Tehran's possession of the bomb could trigger an arms race between Iran and Israel. Israel bombed an Iraqi facility in 1981.

Israel has never confirmed being a nuclear power, but it is widely believed to have as many as 100 to 200 such weapons.

Iran denies that it intends to make nuclear weapons and says it seeks nuclear power as an alternative source of energy as its oil reserves diminish.

With Russian assistance, Iran is building its first nuclear. The official Islamic Republic News Agency reported Thursday that its second nuclear reactor will have a capacity of 1,000 megawatts.

The United States suspects Iran of developing a clandestine nuclear weapons program and has lobbied for the International Atomic Energy Agency to declare the country in violation of the Nuclear Non-Proliferation Treaty.

The IAEA, a U.N. watchdog, has been pressing Iran to allow unfettered access to its nuclear sites.