The political wing of the Ulster Defence Association (UDA), blamed for about 400 murders in its campaign to maintain British rule during three decades of civil strife, said it had put the remainder of its arsenal beyond use.
"Today the leadership of the UDA can confirm that all weaponry under its control has been put verifiably beyond use," said Ulster Political Research Group (UPRG) leader Frankie Gallagher.
The move, a month before a long-running amnesty on giving up arms ends, was facilitated by the Independent International Commission on Decommissioning (IICD) under the leadership of Canadian General John De Chastelain.
It was verified by two independent witnesses, the former Church of Ireland primate, Lord Robin Eames, and former top civil servant George Quigley.
Weapons 'put beyond use'
The UDA is the largest and last loyalist paramilitary group to hand over its weapons following the 1998 Good Friday Agreement which largely ended three decades of violence in the province known as the Troubles.
Loyalists are Northern Ireland Protestants who want the province to remain part of Britain and are historic foes of Catholic republicans, who believe it should become part of the Republic of Ireland.
The other main loyalist groups, Ulster Volunteer Force (UVF) and Red Hand Commandos (RHC), announced last June that they were putting all of their weapons beyond use, a move hailed by political leaders as an "historic day".
The Irish Republican Army (IRA), the main republican paramilitary group, finished destroying its arsenal four years ago, overseen by the commission.
Irish Prime Minister Brian Cowen welcomed the UDA's announcement as "a further significant milestone in the peace process".
"Taken together with the completion of decommissioning by the IRA and the UVF, it is a clear signal that Northern Ireland has moved on and that the democratic institutions established by the Good Friday Agreement are the means through which the entire community in Northern Ireland, and the people of these islands, can and will build lasting peace and prosperity," he said.
'Major act of leadership'
Britain's Northern Ireland Secretary Shaun Woodward said it was a "major act of leadership by the UDA and further comprehensive evidence of the success of politics over violence in Northern Ireland".
The 1998 peace accord ended most of the violence which had plagued Northern Ireland for decades, killing at least 3,500 people.
Devolved self-rule is now in place after a landmark accord in 2007 between the Protestant Democratic Unionists (DUP) and Catholic Sinn Fein.
Sinn Fein lawmaker Gerry Kelly also welcomed the UDA's disarmanent, saying: "This process has been about taking the gun out of Irish politics".
Loyalist groups began disarming in 2008 but the process was suspended after two British soldiers and a policeman in Northern Ireland were shot dead by dissident republicans in March last year.
The process restarted after reassurances from the British and Irish governments that those responsible for the attacks "would be vigorously pursued".
