The Taoiseach and the British Prime Minister were studying a new communication from the IRA which they hoped would demonstrate that the organisation was irrevocably stepping away from active paramilitarism.
Mr Ahern returned to his office after 10 p.m. last night to assess the merit of an IRA response clarifying aspects of a statement which the IRA issued to the governments on Sunday night.
The clarification note was also being relayed to the British Prime Minister, Mr Tony Blair.
"It is not yet clear if the clarifications will be enough," a Government spokeswoman told The Irish Times late last night.
"There isn't a lot of time. It is still viable, but it is getting narrow," a Department of Foreign Affairs spokesman told The Irish Times.
One source late last night advised caution. It was still problematic whether the latest clarification would be enough to persuade Mr Blair and Mr Ahern to return today to Hillsborough to issue their joint declaration on restoring devolved government to the North .
A Government spokeswoman said Mr Ahern and the Minister for Foreign Affairs, Mr Cowen, were late last night studying the IRA clarification. They would consult with the British government and other parties before issuing a definitive response. The Government would review the situation this morning.
The clarification from the IRA was received by Irish officials around 9 p.m., though it is not clear if the IRA produced a written text or whether it was offered verbally.
The Taoiseach, Mr Cowen and key officials, met in Government Buildings shortly after 10 p.m. following Mr Ahern's return from the Isle of Man.
Last night, Government sources were cautious about whether the IRA had gone far enough to break the log-jam in the process, though "the door is not closed", according to one source.
Mr Ahern discussed the IRA's original statement, which was received late on Sunday, during an early telephone conversation yesterday with Mr Blair.
Dublin and London said the Sunday night statement represented progress, but still did not provide the "clarity and certainty" necessary to demonstrate that the IRA war was effectively over.
In an atmosphere of nervous brinkmanship, the British and Irish governments earlier held out against an angry statement from the Sinn Féin president, Mr Gerry Adams, who said the IRA statement was "unprecedented".
Mr Adams contradicted the governments' assertion that the secret IRA statement, which was to be published after the Hillsborough blueprint was released, did not spell out the IRA's future intentions.
"I have seen and read closely the IRA statement. It is clear and unambiguous. The two governments have acknowledged that the IRA statement is positive.
"I therefore find it incredible that they have not acted on the basis of this unprecedented intervention."
Mr Adams said if the governments' request for clarification was genuine then the IRA should provide it. That clarification came last night.
There was also speculation yesterday that the IRA was preparing for a major act of decommissioning, and this could possibly come before the blueprint was published. One republican source said he though such an act would be more likely after the governments' proposals were published.
A spokesman for Gen John de Chastelain's decommissioning body said yesterday that no IRA disarmament had taken place by then.
The governments, according to informed sources, posed three questions to the IRA which translate into a central request that the IRA state, in language of its own choosing, that it is effectively standing down. The two governments were last night considering whether the clarification met that requirement.
The Northern Secretary Mr Paul Murphy, in a statement to the Commons yesterday acknowledged that what the governments wanted from the IRA was, if granted, historically groundbreaking.
