At least eight Unionist MPs have been warned their lives could be in danger from dissident republicans opposed to the Belfast Agreement, it emerged tonight.
They were told to review personal security measures after fresh intelligence revealed dissident terrorist were preparing to strike against an unnamed senior politician.
It is understood those alerted include Stormont First Minister Mr David Trimble, who is to have talks with the Taoiseach Mr Ahern and British Prime Minister Mr Tony Blair tomorrow, and the Democratic Unionist leader the Rev Ian Paisley.
Northern Ireland's acting chief constable Colin Cramphorn refused to discuss the death threat when he briefed policing board members in Belfast.
But a senior security source tonight confirmed rogue republicans were behind the targeting.
He said: "We are treating this very seriously, otherwise we wouldn't have warned these people."
East Belfast DUP MP Mr Peter Robinson, who is among the eight, claimed: "I was told the attacks were at an advanced stage of planning."
His wife Iris, the Westminster representative for Strangford, and North Belfast MP Mr Nigel Dodds were also tipped off by police.
Mr Ian Paisley Jr, a DUP member of the Stormont Assembly and policing board who features on dissidents' hit-list, told how he learned of the murder plot.
"Last night and today a number of politicians were formally warned by police of a serious republican threat to carry out either a political assassination or a 'spectacular'."
Despite Mr Cramphorn's assessment that dissident republicans posed the main threat, Mr Paisley insisted the Provisional IRA was linked to the threat against unionist politicians.
"The term dissident is a very convenient one for the Government and police to use because it covers a multitude of sins," he said.
"The reality is that the IRA hasn't gone away," he added.
Ulster Unionist Lagan Valley MP Mr Jeffrey Donaldson was also aware of new terrorist threats against Ulster Unionists.
He said: "It is clear there is a high level of activity at the moment by republicans.
"They are determined to undermine the democratic process in Northern Ireland," he added.
PA