Former Secretary of State Colin Powell is demanding answers from the CIA and Pentagon after an Iraqi defector stepped forward to admit that he fabricated claims that Saddam Hussein had weapons of mass destruction in advance of the U.S.-led invasion of Iraq in 2003.

Powell — who has stated that his prewar speech to the United Nations accusing Iraq of harboring weapons of mass destruction was a "blot" on his record — spoke out a day after Rafid Ahmed Alwan al-Janabi told the Guardian newspaper that he made up claims of mobile biological weapons and clandestine factories when making reports to Germany's intelligence service, the BND.

The BND had approached Janabi, who was codenamed "Curveball" by U.S. and German intelligence officials, in 2000 and again in 2002 looking for inside information about Iraq.

"They gave me this chance. I had the chance to fabricate something to topple the regime," Janabi told the British newspaper. "I and my sons are proud of that and we are proud that we were the reason to give Iraq the margin of democracy . . . Maybe I was right, maybe I was not right. I had a problem with the Saddam regime, I wanted to get rid of him and now I had this chance."

The revelations shocked Powell, who presented America's case against Saddam in a Feb. 5, 2003, speech to the United Nations.

"It has been known for several years that the source called Curveball was totally unreliable," Powell told the Guardian. "The question should be put to the CIA and the DIA [Defense Intelligence Agency] as to why this wasn't known before the false information was put into the NIE sent to Congress, the president's State of the Union address and my 5 February presentation to the U.N."

The DIA is the Defense Department's intelligence arm. The NIE is the National Intelligence Estimate, a classified document that reflects the views of America's 16 intelligence agencies and is given to key policymakers.

In his speech, Powell made mention of "firsthand descriptions of biological weapons factories on wheels and on rails . . . The source was an eyewitness who supervised one of these facilities." That source was Janabi, who now admits it was all a lie.

That fateful presentation by the soldier-diplomat to the world body lent considerable credibility to then-President George W. Bush's case against Iraq and for going to war to remove Saddam from power. Bush and other high U.S. officials cited the threat posed by Iraqi biological weapons as justification for the U.S.-led invasion in 2003.

"I'm the one who presented it to the world, and (it) will always be a part of my record. It was painful. It is painful now," Powell said in an 2005 interview with Barbara Walters. In the speech, Powell said he had relied on information he received at CIA briefings.

Although he told Walters that then-CIA Director George Tenet "believed what he was giving to me was accurate," Powell admitted that "the intelligence system did not work well . . . There were some people in the intelligence community who knew at the time that some of those sources were not good, and shouldn't be relied upon, and they didn't speak up.

"That devastated me," he said.