The Ulster Volunteer Force (UVF), the Red Hand Commando (RHC) and the Ulster Defence Association (UDA) have confirmed reports that they have carried out major acts of disarmament.
The weapons were destroyed as part of a process overseen by the Independent International Commission on Decommissioning (IICD). It is understood the decommissioning happened in the last month.
At a press conference in east Belfast yesterday morning, the UVF said it had destroyed its entire arsenal, with a further major disarmament act from the RHC.
The UVF/RHC statement said the process had begun last autumn but had been suspended following the dissident republican killings of a policeman and two British soldiers in March.
At a press event at the East Belfast Methodist Mission, senior UVF members read the statement in which they announced that all arms had been put beyond use.
The UVF leadership said: "We have done so to further augment the establishment of accountable democratic governance in this region of the UK, to remove the pretext that loyalist weaponry is an obstacle to the development of our communities and to compound our legacy of integrity to the peace process."
Photographers and TV camera crews were instructed not to film as the statement was delivered.
After the statement was read out, Dawn Purvis, leader of the UVF-aligned Progressive Unionist Party (PUP), welcomed the move.
"This is a truly momentous day in the history of progressive loyalism. The decommissioning of all weapons by the UVF and RHC shows that peaceful, stable, inclusive democracy is the way forward for our country," she said.
She praised the efforts of the late David Ervine who once led the PUP and who she said worked to build peace and end division.
While the Democratic Unionist Party (DUP) had met with loyalist groups, Ms Purvis made an apparent sideswipe at reports the party played a key role in delivering decommissioning.
"For those involved, decommissioning was a process, carefully managed and brought to fruition, not an event, and contrary to some reports, not delivered as a result of two meetings in the space of nine months," said the PUP Assembly member.
PUP representative Billy Hutchinson confirmed the UVF move. "The UVF have decommissioned all weapons", he said. "It is complete", he added.
In a separate statement, the UDA confirmed it had decommissioned a portion of its illegal arsenal and had started a process that would lead to the destruction of all its arms.
The UDA statement said: "This is a courageous and unprecedented move that is part of a wider transition from conflict to peace.
"This process was initiated in autumn 2008 when the Combined Loyalist Military Command was reconvened to address the outstanding issue of Loyalist military material. As a result of those discussions, all constituent parts agreed to set in place the internal arrangements necessary to begin the disarmament process.
"As a result we have held a series of meetings with General John De Chastelain and his team who have witnessed an act of decommissioning. This process will be completed within the previously notified timescale.
"By carrying out this act we are helping to build a new and better Northern Ireland where conflict is a thing of the past."
"The struggle has ended," the UDA added. "Decent democracy has been secured. And the need for armed resistance has gone. Consequently we are putting our arsenal of weaponry permanently beyond use."
Frankie Gallagher of the UDA-linked Ulster Political Research Group (UPRG) said the announcement marked "a milestone in the history of loyalism".
"It is a day of hope and joy, a day that should be built on by the whole of Northern Ireland and should be grabbed by both hands."
Mr Gallagher praised the work of Martin McAleese, the husband of President Mary McAleese. Mr McAleese has held several meetings with the UDA in recent years and is a friend of Jackie McDonald, the so-called UDA brigadier in south Belfast.
He said "I think the role of Martin McAleese has been a positive one."
Minister for Justice Dermot Ahern welcomed the move and said he has been kept fully briefed by the Independent International Commission on Decommissioning on developments.
The Minister said he expects that he and the Secretary of State for Northern Ireland will receive a formal report from the IICD "at an appropriate stage reflecting the positive developments which have taken place."
The UVF killed 550 people during the Troubles, while the UDA, which also operated under the flag of convenience of the Ulster Freedom Fighters (UFF), claimed 431 lives.
The Red Hand Commando, a splinter group allied to the UVF, killed 19 people.
Most of the groups' victims were Catholic civilians.
Earlier this month it emerged that the loyalist groups had taken moves to begin decommissioning all their weapons - as the IRA did four years ago.
The move was welcomed by the Irish and British governments at the time, but they said that they were awaiting official confirmation of the disarmament act, and information on the scale of arms cache destroyed, in a formal report from the IICD due to be published in August.
But after news of the decommissioning leaked out, it had been expected that the loyalist groupings would take steps to confirm they had started to destroy their illegal weapons.
The UVF campaign of violence stretches back to the mid-1960s when loyalists lashed-out over the 50th anniversary of the 1916 Rising and against early calls for full civil rights for Catholics in Northern Ireland.
In 1966 it killed two Catholic men, John Scullion and Peter Ward, plus Protestant woman Matilda Gould who was caught up in an attack on a Catholic owned bar next to her home.
The UVF carried out the Dublin and Monaghan bombings in 1974 which caused the largest single loss of life in the conflict, killing 33 people.
The group killed 550 people during the Troubles, while the UDA, which also operated under the flag of convenience of the Ulster Freedom Fighters (UFF), claimed 431 lives.
The Red Hand Commando, a splinter group allied to the UVF, killed 19 people. The UDA was formed in 1971 and is the largest paramilitary group in Northern Ireland, once boasting tens of thousands of members.
It controversially remained a legal organisation until as recently as 1992 when it was banned by the then Secretary of State Sir Patrick Mayhew.