Tony Blair's talks with Irish premier Bertie Ahern and the pro-Agreement parties on Thursday will be his "last chance" to deal with the situation in Northern Ireland, David Trimble has said.

The Ulster Unionist leader warned the British Government risked losing public support unless action was taken to end violence on the streets.

Mr Trimble's warning comes after another weekend which saw serious disturbances in east and west Belfast.

Nationalists attacked police after an Orange Order parade on the Springfield Road on Saturday.

The violence followed an Orange Order parade

Earlier in the day a house in a Protestant area of east Belfast was destroyed after nationalist petrol bombing. Sinn Fein said it came after loyalists threw pipe bombs at Catholics.

"I think this might actually be Tony Blair's last chance to get a grip on the situation," he said.

"I do have to emphasise that the situation in Northern Ireland has deteriorated very sharply over the course of the last month or two.

"That sort of rioting is now almost a nightly event.

'Orchestrated'

Mr Trimble, who is Northern Ireland's first minister, said it was clear the trouble was orchestrated by paramilitaries but "primarily by the republican movement".

"We've had a serious increase of violence and no effective action so far by the government in response to this.

Tony Blair faces calls for sanctions

"The inevitable consequence of that is that support for the present arrangements is rapidly vanishing."

Unionists are expected to use Thursday's talks to push for sanctions against Sinn Fein.

Speaking on Sky television's Sunday with Adam Boulton programme, the Ulster Unionist leader stressed that he wanted to see Prime Minister Tony Blair "place some effective political measures to put pressure on the republican movement".

Security assessment

Thursday's crisis talks were called two weeks ago amid diminishing confidence in the peace process.

It followed revelations that a security assessment said the IRA had been developing and testing new weapons in Colombia.

The document, which was shown to the BBC, said the operations in South America were sanctioned by two leading members of the IRA's army council.

Republicans have also been implicated in the break-in at a Special Branch office at the Castlereagh police complex in Belfast.

Mr Trimble said the worrying thing was "the question of why is the IRA researching new weapons, continuing to target, continuing to acquire equipment that can only be used for a fresh campaign".