The largest of Northern Ireland's Protestant paramilitary groups, the outlawed Ulster Volunteer Force, has renounced violence and pledged to disarm.

This breakthrough in the decade-long Northern Ireland peace process, announced Thursday, comes just four days ahead of deadline for forming a new Catholic-Protestant power-sharing government in Belfast.

Ulster Volunteer Force founder Gusty Spence said the stand-down will take effect at midnight. He said the UVF has ceased all recruitment and military training, and has stopped targeting opponents.

A spokesman for British Prime Minister Tony Blair welcomed Thursday's announcement, but said the prime minister wants to see the pledge "translated into action."

In January, Northern Ireland's largest Catholic party, Sinn Fein, cleared away one of the last obstacles to power-sharing, when its members voted to begin cooperating with the Protestant-dominated police force.

The Ulster Volunteer Force was formed in the 1960s to fight the largely Catholic Irish Republican Army - the military wing of Sinn Fein that was seeking an end to British rule in the province. Authorities say the UVF killed more than 400 people, mostly civilians, during its 30-year reign of terror.

The group declared a ceasefire with the Irish Republican Army almost 14 years ago, but has been linked to deadly attacks since then against its breakaway Protestant rival, the Loyalist Volunteer Force.

Some information for this report was provided by AFP and AP.