Two battalions of British troops are leaving Northern Ireland because of improved security conditions in a long conflict over British rule, the province's police chief announced on Tuesday.

"The withdrawal of these two battalions to Great Britain will be completed within the next two weeks," said a statement issued by Ronnie Flanagan, head of the Royal Ulster Constabulary.Military sources said about 400 troops were being withdrawn, while a similar number had left during the course of the summer. This would cut Britain's garrison in the province to around 16,000.

But both battalions will remain under the command of the province's army commander and could be returned from mainland Britain immediately if needed.

Political allies of Northern Ireland's main guerrilla groups signed the so-called "Belfast Agreement" in April along with politicians from other pro-Irish Catholic and pro-British Protestant parties.

The agreement, intended to draw a line under 30 years of violence in which more than 3,600 people have been killed, provides for continued British sovereignty while a majority in the province want it, and the creation of closer all-Ireland links.

Northern Ireland's major guerrilla forces are operating cease-fires in their war over the future of British rule in the province.

Dissident republicans in the breakaway Real IRA called off hostilities after provoking public outrage by detonating a bomb in the town of Omagh that killed 29 people last month.