A huge explosion ripped through the living quarters of a suburban army base at breakfast time Monday, killing one soldier and burying others. The outlawed Irish Republican Army said it was responsible for the blast.

The IRA, which is fighting to end British rule of Northern Ireland, said it planted a bomb at the Inglis Barracks near the north London parfliamentary district of Prime Minister Margaret Thatcher.One witness said a section of the long two-story barracks "was demolished like a pack of cards."

Scotland Yard said one soldier was killed and nine others injured, one of them critically.

Early this afternoon a Scotland Yard spokesman said experts were not certain what caused the explosion, but he did not dispute the IRA's bomb claim and London gas company officials virtually ruled out a gas explosion.

It would be the first successful bombing in mainland Britain by the IRA since Oct. 12, 1984, when the organization blasted a Brighton hotel in which Thatcher was staying, killing five people.

The large Inglis Barracks base is a headquarters for up to 1,000 army royal engineers and for the armed forces postal and courier service. Experts said it would be considered a "soft target" for the IRA.

The nationalist guerrillas were angered when in March this year British SAS commandos shot and killed three unarmed IRA "volunteers" who were in Gibraltar to carry out a bombing.

Col. William Butt, who was in the London barracks today, said, "The outer walls blew out and the roof caved in. We rushed in and were able to pull out some of the bodies."

He said one of the injured was trapped under fallen masonry for 30 minutes and several had to be dug out by hand. "One man was saved by a radiator being completely across his body," Butt said.

The IRA said only that it was responsible for bombing the base. It made the claim in Dublin and in a call to the British Broadcasting Corp. in Belfast.

The IRA's previous attack on British troops outside Northern Ireland came July 14 when two bombs ripped through the living quarters of an army base in Duisburg, West Germany, wounding nine British soldiers. In the Netherlands on May 1, IRA machine gun and bomb attacks killed three Royal Air Force men.

Thatcher got word of the explosion arriving in the city of Perth on a trip to Australia. "I have sent a message saying I'm very distressed," she said. "It's on the edge of my constituency."

The IRA has made it clear that Thatcher remains the organization's No. 1 target for assassination. Commentators said the IRA has recently been attacking military targets in order to try to stimulate a "British troops out of Ireland" drive.