The historic move could be announced this Wednesday, said the sources, as Sinn Fein's chief negotiator, Martin McGuinness, arrives in the US to brief supporters and White House officials.
In Belfast yesterday Mr McGuinness told the BBC that the announcement on IRA decommissioning will be "more significant" than the 1994 ceasefire.
It's understood that the sealing of a mass cache of IRA arms, including Semtex, heavy-calibre machine guns, small arms and tens of thousands of rounds of ammunition, has been overseen by the Canadian General John de Chastelain.
Mr McGuinness said: "General de Chastelain, when he deliberates on all of this and explains to the world whatever work he is engaged in with the IRA, will then make an announcement which, I think, may be of much more significance than the events of the summer of 1994 or even the 28 July statement."
It was thought significant disorder involving loyalists in recent weeks could stall the IRA move, first promised in July, when the paramilitary organisation said it was dropping its armed campaign in favour of a political way forward.
Last night a senior republican source in Belfast told The Independent on Sunday: "What we will see over the next few days is an announcement that weapons have been put beyond use.
"McGuinness is travelling to America on Tuesday, so we expect a statement from the IRA and then from the General, probably on Wednesday."
Mr McGuinness's statement yesterday came 24 hours after the Irish Foreign Affairs Minister, Dermot Ahern, revealed that talks with Sinn Fein had indicated a move on decommissioning soon.
The Irish Prime Minister, Bertie Ahern, met Sinn Fein leaders in Dublin on Friday, in his first formal talks with them since the IRA was accused of last December's Northern Bank robbery in Belfast.
In the UK, Tony Blair has been briefed on the expected moves. The Prime Minister will be hoping that the IRA decision can be followed by new talks on restoring a devolved administration to Northern Ireland.
Although publicly loyalist politicians insist the IRA move will require a long assessment period, privately Northern Ireland Office officials believe devolution could be re-established by January.Reuse content