The Taoiseach has warned Sinn Féin that events like the attempted abduction of a dissident republican in Belfast made it more difficult to resist calls for the party to be excluded from the peace process.
The provisional IRA have been blamed for an attempted abduction of Bobby Tohill last weekend. They have denied authorising the kidnapping.
But Mr Ahern told Martin McGuinness that the incident undermined the prospects for any political movement from the DUP.
Ahead of a meeting between a Sinn Féin delegation and the Taoiseach, SF’s Martin McGuinness blamed what he called very determined anti-peace process elements in the PSNI for 'orchestrating' the events of last weekend.
Arriving for a meeting, Mr McGuinness said the incident clearly showed the PSNI wanting to capture the weekend headlines to undermine the role of Sinn Féin in the peace process.
The Ulster Unionist leader, David Trimble, threaten to withdraw from the review of the Good Friday agreement in light of the allegations.
In the House of Commons Mr Trimble said it was utterly unreasonable to expect his party to stay in talks with 'these people'. He threatened to walk out next Monday unless the London government summons up the courage to act.
The British Prime Minister Tony Blair said he would act against Sinn Fein if what he described as ‘mainstream IRA’ are found to have been involved.
Mr Blair warned Sinn Féin and the IRA they could not be allowed to talk about human rights one day, and then start beating human rights out of people the next.