David Trimble has issued a warning to Tony Blair, saying his meeting with Bertie Ahern and pro-Belfast Agreement parties will be his "last chance" to deal with the situation in Northern Ireland.
In what is seen as another attempt to force the British government into sanctioning Sinn Féin, Trimble said the British government risked losing public support unless the situation was resolved.
Trimble's comments come as tensions between Protestant and Catholic communities in Belfast continue to grow. There have been serious disturbances in Belfast recently involving both communities and the police service. The PSNI yesterday employed the use of water cannon against nationalist protestors following a contentious Orange Order march in the city.
"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. It's not just last night's violence. That sort of rioting is now almost a nightly event.
"The inevitable consequence of that is that support for the present arrangements is rapidly vanishing."
Mr Trimble claimed the trouble was orchestrated by paramilitaries and "primarily by the republican movement".
The talks are scheduled for next Thursday.