LONDON — Lasting peace in Northern Ireland took another step forward Saturday when major Protestant paramilitary organizations announced that they had decommissioned some or all of their weapons, following a similar move years earlier by the opposing Irish Republican Army.

The Ulster Defense Association and the Ulster Volunteer Force, two fearsome groups responsible for hundreds of civilian deaths, said the time had come for peace and democracy in a territory riven for decades by deadly conflict between Catholics and Protestants.

“The need for armed resistance has gone. Consequently we are putting our arsenal of weaponry permanently beyond use,” the Ulster Defense Association said in a statement. It added that it had begun destroying some of its arms in the presence of independent monitors and would continue until the process was complete.

The Ulster Volunteer Force said that it had fully given up its stockpile. The declaration was made at a Belfast news conference by a spokesman who appeared unmasked and dressed in civilian clothes, in a marked change from the days when members issued statements wearing ski masks and toting guns.

The group’s weapons were “totally, and irreversibly, beyond use” in order to boost “the establishment of accountable democratic governance in this region of the United Kingdom (and) to remove the pretext that loyalist weaponry is an obstacle,” the spokesman said.

For years, the two paramilitary organizations carried out attacks on Catholic neighborhoods in their campaign to ensure that Northern Ireland remained part of the United Kingdom. Both claimed responsibility for hundreds of shootings, bombings and other acts of violence estimated to have killed nearly 1,000 people during Northern Ireland’s so-called “Troubles,” in which more than 3,500 people died.

The historic 1998 Good Friday Agreement between loyalists and republicans largely brought an end to armed conflict and called for a full relinquishing of weapons on both sides.

In 2005, independent monitors confirmed that the Irish Republican Army had put its arsenal beyond use. But a number of loyalist paramilitaries refused to follow suit, insisting that they needed to keep their guns for protection.

Saturday’s announcements came after increasing pressure on the Protestant underground groups from the British government. Late last year, the minister in charge of Northern Irish affairs, Shaun Woodward, said that the amnesty period for turning in weapons with no questions asked would expire sometime in 2010.

Woodward welcomed the announcements Saturday.

“For those who have doubted the political process, it is proof that politics works and that guns have no place in a normal society,” he said.

Dawn Purvis, a member of the Progressive Unionist Party, which has been linked to loyalist paramilitaries, said: “It is time to move on . … Peaceful, stable democracy is the way forward for Northern Ireland.”

But sectarian strife is by no means over in Northern Ireland. In March, splinter republican groups killed two police officers and two British soldiers, raising fears that the “dark days” of open conflict could return.

But politicians on both sides of the divide condemned the shootings and vowed to forge ahead with the peace process.

The Ulster Volunteer Force said Saturday that it had begun preparing to get rid of its weapons last autumn but broke off because of the killings. But it resumed after receiving assurances that authorities wholeheartedly would pursue those responsible.

Tensions across the religious divide probably will flare with the annual “marching season” about to get under way, when partisans, mostly on the Protestant side, hold parades to declare their loyalties.