The head of the U.N. nuclear agency said Saturday that documents found at the home of an Iraqi scientist appear to outline high-tech attempts to enrich uranium in the 1980s.

Other senior agency experts, however, said the method outlined -- which could be used to make nuclear weapons -- proved too sophisticated for the Iraqis to exploit at the time.

U.N. nuclear chief Mohamed ElBaradei, who oversees the U.N. review of Iraq's nuclear program, told The Associated Press the research outlined in the documents had "something to do with laser enrichment."

He said the importance of the find appeared to be whether the Iraqis had included the information in their 12,000-page declaration submitted to the United Nations last month.

Iraq denies it has any more banned weapons. The United States and Britain insist it does and threaten to disarm Iraq by force unless it gives up those weapons and cooperates fully with the U.N. inspectors.

"If it's something we did not know about, it obviously doesn't show the transparency we've been preaching," ElBaradei said, alluding to U.N demands that Baghdad be more forthcoming with U.N. inspectors.

The Iraqis claim the declaration submitted last month proves that their country no longer owns or is developing nuclear, chemical or biological weapons. Top U.N. inspectors say the document was incomplete and failed to support Baghdad's claims to have destroyed the banned weapons.

The documents were found Thursday by U.N. inspectors in the home of 55-year-old physicist Faleh Hassan, once associated with his government's nuclear program. It was inspectors first unannounced call on a private home in Iraq.

Hassan said that when an accompanying Iraqi official left his side momentarily, a female U.N. inspector offered to arrange for him to leave Iraq as an "escort" so his ailing wife could undergo treatment for kidney stones, diabetes and high blood pressure. He said the woman making the offer was an American, but that he could not remember her name.

Hassan said he refused the offer. "This is Mafia-like behavior," he told reporters.

Hassan, director of the Al-Razi military industrial site, said the documents were from his own private research work and the graduate theses of students he has advised. ElBaradei, in a television interview, said the documents were official and defended the inspectors' conduct.

Under a U.N. resolution approved in November, inspectors are allowed to speak to Iraqi scientists in private and even take them out of the country for interviews, a requirements Washington hopes will prompt them to reveal secrets.

Iraqi officials have said they do not believe it is necessary for scientists to be taken out of the country, but will allow the measure if a scientist consents.

Iraqi officials said Hassan is not on a list of 500 scientists and other specialists connected with nuclear, biological and chemical programs submitted to the United Nations last month.

ElBaradei and Hans Blix, who heads the U.N. search for biological and chemical weapons, arrived to Larnaca on Saturday for an overnight stay before setting off for Baghdad Sunday for two days of consultations with the inspectors and meetings with Iraqi officials.

The are to report Jan. 27 to the Security Council on Iraq's cooperation and the findings of the inspectors. The report could tip the scale toward war or peace.

Blix and ElBaradei said Saturday that Baghdad needed to do more to convince the world it was not hiding anything.

"Iraq has not cooperated sufficiently with the United Nations weapons inspectors, and we will impress the seriousness of the situation to them," Blix told reporters as he arrived at his hotel in Larnaca on the southeast coast of Cyprus.

ElBaradei, speaking to the AP on his flight from Vienna to Larnaca, said he will tell Iraqi officials they need "to shift gear ... and come forward and declare everything to exonerate yourselves."

He alluded to growing U.S. exasperation with Iraq -- and the rising possibility of war as Baghdad continues to drag its feet on full compliance with the inspections regime.

"If we continue to say we cannot find a smoking gun but we cannot exclude the possibility because we haven't seen all the evidence, this is not going to be sufficient," he said. "Time is running out ... the international community is really getting impatient."