US citizens also provided "financial and material support" for armed groups in Northern Ireland: much of the funding for the Irish Republican Army, for example, came from Irish-Americans.

"Contrary to common belief, the American export of terrorism or terrorists is not a recent phenomenon," the report said.

"Nor has it been associated only with Islamic radicals or people of Middle Eastern, African or South Asian ethnic origin."

'Simply to provoke thought'

The CIA concluded that foreign governments would be less likely to cooperate with the US on detention, intelligence-sharing, and other issues.

"If the US were seen as an exporter of terrorism, foreign partners may be less willing to cooperate with the United States on extrajudicial activities," the report noted.

George Little, a CIA spokesman, said in a statement that the document was merely a think piece - one of many prepared by the agency.

"These sorts of analytic products, clearly identified as coming from the agency's 'red cell', are designed simply to provoke thought and present different points of view," he said.

Wikileaks has released dozens of leaks over the years, but it gained particular attention last month, when it published more than 75,000 classified US military documents on the war in Afghanistan. It has promised to release another 15,000 in the coming weeks.

Wikileaks was heavily criticised by the US government for endangering the lives of Afghan informants and others who work with the US military.

In a separate development, Sweden's chief prosecutor said she will continue investigating an accusation of molestation against Julian Assange, the founder of Wikileaks.