The US government is backing the demands by the Taoiseach and British Prime Minister for an end to all paramilitary and criminal activity in Northern Ireland.
A State Department spokesman said the decision by the IRA to withdraw its offer of decommissioning was unwelcome.
In Derry, the Minister for Foreign Affairs, Dermot Ahern, has been discussing the implications of the recent IRA statements with the SDLP and Sinn Féin.
Meanwhile, Archbishop Sean Brady has urged all sides in the peace process to temper their language and recommit themselves to the task of making a better society for all.
Taoiseach notes distancing by Sinn Féin
The Taoiseach has said he has noted the distancing of Sinn Féin's comments from yesterday's IRA statement.
A statement released by the republican paramilitary group yesterday evening to RTÉ News said the seriousness of the impasse in the peace process should not be underestimated.
Speaking in Athlone this morning, the Taoiseach said he had not changed his view on the IRA position from that which he expressed yesterday.
He added that the minister would be giving the Government's view to Mark Durkan of the SDLP and Martin McGuinness later.
Asked if he considered yesterday's second statement by the IRA to be a threat, Mr Ahern said his policy was not to comment on IRA statements.
'We never have commented for 30 years on IRA statements and we are not going to now', he said.
He also refused to comment on the role of the Sinn Féin leadership in the present situation, and its criticism of the Minister for Justice, Michael McDowell.
Meanwhile, the deputy chair of the North's policing board, Denis Bradley, has said he believes there are tensions within the republican movement.
Speaking on RTÉ Radio, Mr Bradley added that this is a critical moment in the peace process.
Kenny voices concerns
Earlier, the Fine Gael leader, Enda Kenny, said he was concerned that the leadership of Sinn Féin was apparently either unable or unwilling to interpret the latest statement from the IRA.
Mr Kenny said it was tantamount to a threat against the Irish people and the State. He said such threats have no place in any process of negotiations, and that democratic political parties must stand firm against intimidation.
He said his party will use its Dáil Private Members' time next week for a debate which would allow all elected members to unite in challenging the republican movement to put an end to all paramilitary and criminal activity.
Speaking on RTÉ Radio, Mr Kenny said the contradictions between what the Government and republicans were saying about such activities were at the centre of the current impasse.
The Labour Party has described the statement as a sinister development, while the Green Party said it was extremely intimidating in the language and tone used.
Last night the Minister for Finance, Brian Cowen, said it was his personal view that there was no role for paramilitaries in modern Ireland.
