TEHRAN -- Iran on Friday strongly rejected U.S. claims that Tehran sheltered leaders of Al-Qaeda, a terror network accused of masterminding September 11 bombings, and that the country was on the track to produce arms of mass destruction.

"Such statements are at odds with the political literature and unbecoming of those who boast of being political," Foreign Ministry spokesman Hamid-Reza Assefi said.

"The repetition of such baseless claims cannot portray them as valid and credible," IRNA quoted Assefi as saying.

Secretary of Defense Donald Rumsfeld on Thursday repeated Washington's earlier accusations that Al-Qaeda leaders were operating from havens like Iran.

Rumsfeld, who has previously accused Iran of giving refuge to Al-Qaeda members fleeing Afghanistan, provided no details on which the group's leaders are believed to be in Iran.

Tehran has repeatedly rejected sheltering the suspected terror network's elements. It has also arrested several hundreds of them and handed them over to their country of origin.

Meanwhile, White House National Security Advisor Condoleeza Rice on Wednesday renewed Washington's accusations that Tehran supported terrorism and sought to acquire weapons of mass destruction.

Without giving any evidence, she accused Iran of behavior U.S. considers detrimental to its interests, including alleged support for terrorists and making efforts to acquire nuclear weapons.

Assefi said, "The Islamic Republic of Iran, in line with its principles, is very serious and firm about the fight against terrorism and its nuclear programs are very transparent and intended for peaceful intentions".

"America's selective policies in addition to its double standards as well as its support for terrorism, do not put it in a position to judge about others," he added.

Rice said in Washington Wednesday that the U.S. has raised alarm over these (weapons of mass destruction) programs over a long period of time.

The statements came ahead of an expected report at the June meeting of the International Atomic Energy Agency by IAEA Executive Director Mohamed ElBaradei amid reports that Washington was pressuring the top nuclear watchdog to say Iran committed violations of the 1970 Non-Proliferation Treaty (NPT).

Iran says its nuclear programs are only intended to generate 7,000 megawatts of power in the next 20 years to cope with rising demand for energy in the country while its hydrocarbon reserves become over-stretched.