The IRA said in a statement it would cease all armed activity from 4pm on Thursday and pursue its aims through politics - a crucial move to revive talks on a lasting political settlement in the violence-torn province. It said its units must "dump arms".
The statement read in part: "The leadership of Oglaigh na hEireann (IRA) has formally ordered an end to the armed campaign.
"This will take effect from 4pm this afternoon (Thursday). All IRA units have been ordered to dump arms. All volunteers have been instructed to assist the development of purely political and democratic programmes through exclusively peaceful means."
Sinn Fein president Gerry Adams said on Thursday that the British and Irish governments now had no excuse not to re-establish a power-sharing government in Northern Ireland.
He also said British troops must begin to withdraw from the
province and warned London and Dublin to stop "pandering" to
rejectionists in the pro-British Protestant community.
"There is now no possible excuse for the British and Irish
governments to not fully and faithfully implement the Good
Friday agreement," said Adams, the head of the Irish Republican Army's political ally.
The IRA had been expected to outline plans for its future since April, when its political ally Sinn Fein called for the guerrillas to end armed struggle for a united Ireland.
Crimes it was accused of fanned calls for the group to disband and sparked harsh censure of Sinn Fein from traditional supporters.
Earlier on Thursday, Sinn Fein president Gerry Adams had promised that the widely anticipated statement by the Catholic guerrilla group would "challenge" all parties to the Northern Ireland conflict.
But, speaking before the IRA statement became public, the province's main Protestant party, which favours continued union with Britain, said a deal on reviving a suspended local assembly was still a long way off.
Paisley (C) said he still wanted to
see proof of the IRA's pledge
"I am saying now the proof of the pudding is in the eating and digesting of it," said Ian Paisley, leader of the Democratic Unionist Party (DUP).
"We've heard it all before. You can wrap it up anyway you like ... put a new bit of ribbon on the package but we want the action, the proof this is happening," he told BBC Television.
The pro-British DUP refuses to talk directly to Sinn Fein, still less sit in government with it, while the Catholic politicians maintain links to the paramilitary organisation.
Irish, British response
The IRA arsenal, used to wage a 30-year campaign against British rule until a 1997 ceasefire, has long been the main stumbling block to securing a political deal. Criminality also became a major issue this year after a high-profile robbery and murder.
Earlier in the day, Irish Prime Minister Bertie Ahern cut short a visit to the Galway Races to return to Dublin in anticipation of the statement. Foreign Affairs Minister Dermot Ahern returned from France.
"The leadership of Oglaigh na hEireann (IRA) has formally ordered an end to the armed campaign"
Sinn Fein was to hold press conferences in Dublin and Washington at 1500 GMT and briefings in London and Brussels at the same time. The Irish and British governments were also expected to make a formal response.
Anticipating an IRA move, Britain released on Wednesday night a convicted bomber who was first let out under the 1998 Good Friday peace deal but re-arrested earlier this year.
Some 3600 people died during the three-decade-long "troubles", half of them killed by the IRA.
Talks on reviving an assembly, set up under the 1998 Good Friday peace agreement and in which Catholics and Protestants together ran the province's affairs, broke down at the end of last year after Paisley insisted on photographic proof of the weapons being destroyed.
The IRA refused such "humiliation".
It has allowed international monitors to witness three private acts of decommissioning but would not permit them to reveal any details about the weapons.