U.S. Secretary of State Colin Powell tells the UN Security Council on Feb. 5, 2003, that he's holding a vial that could contain anthrax, in a presentation about alleged weapons of mass destruction in Iraq. ((Mike Segar/Associated Press) )

An Iraqi defector has admitted for the first time he fabricated claims that Saddam Hussein had weapons of mass destruction, Britain's Guardian newspaper reported Wednesday.

In an interview with the newspaper, Rafid Ahmed Alwan al-Janabi said he made up a story told to German intelligence officials throughout 2000 about mobile biological weapons and clandestine factories. His motive was to overthrow the Iraqi government, he said.

The United States used the threat posed by Iraqi biological weapons to justify leading the invasion of the country in 2003.

The invasion caused years of political unrest and sectarian bloodshed, resulting in 100,000 deaths, mostly of civilians. No biological weapons were ever found.

Janabi's information also formed the basis of a speech in 2003 by U.S. Secretary of State Colin Powell before the United Nations Security Council.

The Germans first approached Janabi, a Baghdad-based chemical engineer, in March 2000 and then again in 2002, looking for inside information about Iraq.

"Maybe I was right, maybe I was not right," said Janabi, whom U.S. and German intelligence officials code named "Curveball."

"They gave me this chance. I had the chance to fabricate something to topple the regime. Believe me, there was no other way to bring about freedom to Iraq. There were no other possibilities."