The Labour leadxer, Mr Quinn, welcomed the move, which he described as historic.
He said: "While we don't yet know the extent of the decommissioning undertaken by the IRA, there is no doubt that we are witnessing this week events of truly historic proportions. This indeed seems to be the seismic shift in the thinking of the Republican Movement that we were promised some two years ago.
"There is no doubt that we now have the most favourable conditions for real progress since the signing of the Good Friday Agreement. But if full advantage is to be taken of the new situation, all parties must act in a positive manner and show good faith. All sides must intensify efforts to overcome the distrust and sectarianism that has bedeviled Northern Ireland for so long. There is a particular obligation on the loyalist paramilitarties to honour the statements made that they would follow suit if the IRA started decommissioning.
"The two governments and the political parties in Northern Ireland have put enormous work into bringing the process to this stage. Every person of good will must now work to ensure that the opportunity is not lost to move to a new era of peace and political stability in Northern Ireland and consign political violence permanently to the dustbin of history.