The forgery in a document that purported to show Iraq trying to buy uranium from Niger was discovered by forensic experts, the head of the International Atomic Energy Agency said Saturday.
Mohamed ElBaradei, the agency's executive director, said the experts found anomalies in the signatures, the letterhead and the format of the document. He told the Security Council on Friday the forgery had been compared with authentic documents provided by Niger.
In an interview Saturday, he said that any number of groups would have had an interest in planting the document. It was quoted in a report from British intelligence services last year as Britain and the United States sought to build their case for disarming Iraq.
Asked whose interest the forgery served, he said: "I'm sure there's a lot of people who would be delighted to malign Iraq."
But he said the incident was just a "blip."
"In no way do we want to belittle the importance of intelligence," he said. "People have tried to make a big fuss that this document has been forged.
"The intelligence we need we get from different sources. Some sources are reliable, some sources are less reliable. Some sources have political agendas of their own."
ElBaradei, who told the Security Council on Friday that he did not have evidence that Iraq has a continuing program to develop nuclear weapons, said he needed more time and more information to reach a conclusion.
"We have been getting increasing intelligence information in the last three to four weeks," he said. "Some of it is actionable," and produces immediate visits to suspect sites.
"Other things we cannot act on," he added, like a telephone conversation by a person that had been intercepted and taped.