The FBI is investigating the origin of forged documents indicating that Iraq was seeking uranium from Niger, and one candidate for the forgeries is an Iraqi opposition group, U.S. officials said.
The documents, obtained first by Italy's intelligence service, ended up fooling the CIA and other U.S. intelligence agencies into believing Baghdad was trying to buy uranium ore from the African nation, U.S. officials say.
The documents ended up "tainting" other reliable intelligence on Iraq's weapons programs and undermining the credibility of U.S. intelligence reports, said officials who spoke on the condition of anonymity.
One official said that the documents were provided first to the Italians and then to journalists before they ended up in the hands of the International Atomic Energy Agency (IAEA), which dismissed them as fakes.
FBI spokesman Bill Carter said in an interview that a preliminary inquiry into the documents was undertaken after recent meetings between senior FBI officials and Sen. John D. Rockefeller IV, West Virginia Democrat and vice chairman of the Senate Select Committee on Intelligence.
Mr. Carter declined to comment further, citing a policy of not discussing FBI investigative matters.
Other officials said the FBI has sent agents to Italy and other nations to find out the origin of the documents, and the bureau's counterintelligence agents also are questioning officials at the CIA and State Department. The probe was first reported by Newsweek magazine.
Other intelligence obtained by Britain is considered reliable and indicates Niger had tried to sell uranium ore to Saddam Hussein's government, said officials familiar with U.S. intelligence reports.
President Bush chastised senior advisers, including National Security Adviser Condoleezza Rice and outgoing press spokesman Ari Fleischer, about the uranium intelligence flap and the White House's handling of it several times during the recent trip to Africa.
Spokesmen at the time initially said the White House was provided with bad intelligence from the CIA, only to reverse course a day later and claim the intelligence may still be valid although it should not have been included in a presidential speech.
"The president wanted the matter settled," one official said of Mr. Bush's harsh words for his advisers.
Although it received intelligence from the documents earlier, the CIA did not obtain copies of the forged documents until February 2003 -- months after the Italians first obtained them and after the president's State of the Union address.
A U.S. official said the Italians initially only described the documents to the CIA. Then the State Department obtained a set from a journalist and that led to an investigative trip to Niger by former U.S. Ambassador Joseph Wilson.
Mr. Wilson said Niger's government told him that the country would not sell uranium to Iraq, but also informed him that Iraqis were in the country discussing unspecified commercial transactions, which could have included uranium-ore purchases, the U.S. official said.
CIA Director George J. Tenet testified before a closed hearing of the Senate Intelligence Committee on Wednesday to explain how the tainted intelligence ended up in a major U.S. intelligence-community report and the president's State of the Union speech.
An official said the documents included a letter about the purchase of some 500 tons of uranium ore, supposedly signed by Niger's president, Mamadou Tandja. The signature was found to have been faked.
Another document was described as an October 2000 Niger military document signed by a former foreign minister of Niger.
Besides Iraqi opposition, investigators also say the documents could have been produced by criminals, con men, or a foreign intelligence service.
The six main anti-Saddam groups before the war were the Iraqi National Congress, the Supreme Council for the Islamic Revolution in Iraq, the Kurdistan Democratic Party, the Patriotic Union of Kurdistan, the Iraqi National Accord and the Constitutional Monarchy Movement.
In London on Wednesday, British Prime Minister Tony Blair defended British intelligence on the Niger-Iraq uranium deal before the Parliament.
"The intelligence on which we based this was not the so-called 'forged documents' that have been put to the IAEA, and the IAEA have accepted that they got no such forged documents from British intelligence," Mr. Blair said.
"We had independent intelligence to the effect," the prime minister added.
U.S. intelligence officials suspect the bogus documents were created to exaggerate Iraq's nuclear-arms program as part of an effort to garner international opposition to Baghdad.
The forged documents undermined one element of a National Intelligence Estimate, a major interagency report, that became the basis for part of the president's January speech to Congress.
Officials familiar with the intelligence on Iraq's weapons of mass destruction said it included one passage about efforts by Baghdad to buy yellowcake uranium ore from Niger.
However, the passage in the highly classified report did not have a "footnote" or objection attached to it, indicating it represented a consensus view of all intelligence agencies, including the State Department's Bureau of Intelligence and Research.
Only later in another section of the 90-page classified report did the State Department intelligence office indicate that it doubted the attempted Niger uranium purchases.
"There was no opposition to the main reference to Niger," said one official who has seen the estimate.
According to U.S. officials, the State Department's opposition to the intelligence on Niger uranium in the report was related to the department's doubts about Iraq's purchase of special alloy tubes that were believed to be for building gas centrifuges.