BELFAST (Reuters) - Northern Ireland's police chief said on Wednesday the IRA was not behind a spate of recent attacks that have rocked peace efforts in the province. But Ronnie Flanagan, head of the Royal Ulster Constabulary, said breakaway members of the outlawed guerrilla group may have been involved in the upsurge of violence. "It is my belief that the provisional IRA were not involved in those incidents," Flanagan told reporters in the capital of the British province. He spoke after suspected republican hardliners lobbed mortars at a security base close to the border with the neighbouring Irish republic and as politicians from the region's deeply divided Protestant and Catholic communities struggled to make headway in talks. Flanagan condemned Tuesday's bombing of a security base as a "scandalous attack" but cleared the outlawed Irish Republican Army of involvement. "We believe other republican groupings

were involved in carrying out last night's attack," he said. Flanagan said that dissidents who had broken with the IRA, the largest of the anti-British extremist forces, were becoming significant forces during the latest bout of violence. He said "the IRA remains an organisation which is intact ... which presents a threat to this society." But Flanagan said it was not his job to define "what amounts to a cessation of violence". Politicians from Northern Ireland's Protestant majority have threatened to push for the expulsion of the IRA's political wing, Sinn Fein, from the peace talks because of the new rash of violence. The IRA called a halt to a violent 30-year campaign against British sovereignty last July, paving the way for Sinn Fein to take a seat at the talks alongside seven other parties in a bid to heal divisions. The race is now on to seal a deal on Northern Ireland's future in the face of attacks by extremists opposed to peace. Britain and Ireland, co-sponsors of the talks, want to draw up a blueprint by next month so they can put it to referendums on both sides of the border in late May.