Peter King, the force behind the hearings into homegrown Islamist terrorists on US soil, has offered repeated pronouncements over the threat posed by al-Qaida since 9/11.

But as one Democrat slyly reminded the New York Republican during the committee hearing, King too faces accusations of aiding extremist organisations.

King is a long-time supporter of the IRA, and in the 1980s proclaimed: "If civilians are killed in an attack on a military installation it is certainly regrettable, but I will not morally blame the IRA for it."

King gained further notoriety for his support for the IRA when he was kicked out of a Belfast courtroom during a murder trial. The judge called him an "obvious collaborator", according to an account this week in the New York Times.

King has admitted to few regrets about his support for the IRA, and has likened the group to the ANC in South Africa or the Irgun group fighting the British mandate over Palestine before the second world war.

"It was a dirty war on both sides," he told the New York Times.

King went on to serve as an important channel in talks that led to the Northern Ireland peace deal.

However, the congressman dismisses attempts to draw a parallel between IRA and al-Qaida, arguing that the IRA never carried out attacks on US soil, and that his only loyalty was to the US.