Ahern and Hume discuss the crisis

Suspect Arrested as Leaders Condemn IRA Attack

Hundreds of people have staged a peace vigil, placed floral tributes close to where the officers were gunned down and then queued to sign a special book of condolence.

The double murder shocked the British and Irish Governments and outraged US President Bill Clinton.

The Prime Minister, Tony Blair, ordered an end to all further contact between senior civil servants and Sinn Fein representatives, but SDLP leader John Hume is likely to keep open his lines of communication with the republican leadership.

Balir and Clinton last month - both condemn the violence

Speaking from the EU Summit in Amsterdam, Tony Blair described the murders as "a deliberate act to frustrate progress" in the peace process. Later, a Downing Street statement confirmed that work would continue with the Irish government on the joint paper on the decommissioning of paramilitary weapons, and that the multi-party talks process would continue.

The government received the full support of President Clinton, who has been eager to develop an American role in the Northern Ireland peace process. In a written statement, the President declared: "I am outraged by the callous by the murder by the IRA of two policemen in Northern Ireland. I condemn this brutal act of terrorism."

He went on: "There is nothing patriotic or heroic about these cowardly killings." And he warned against retaliation: "Further violence can only play into the hands of those responsible for the vicious murders."

At the same time, the incoming Irish Premier Bertie Ahern, who had talks with Mr Hume in Dublin, said he would only see Sinn Fein president Gerry Adams on one condition.

Mr Ahern said, "If the issue was talking about the unequivocal restoration of an IRA ceasefire, then we will talk. If it is just to continue going round the houses and getting nowhere, there is no point in the meeting."

Mr Hume, who played a pivotal role in helping to broker the IRA ceasefire in August l994, spoke of his anger over the murders, but insisted he was still prepared to continue his dialogue with Sinn Fein.

The Foyle MP is under pressure inside his own party to call a halt to the discussions, but he said: "My intention is to find out exactly what is going on."

He added: "I apologise to no one for that. It is the duty of everyone to bring to an end the loss of life, like yesterday's murder of two innocent human beings. If dialogue can bring it to an end, it is my duty to do that.

"I will apologise for failing - but not for trying. It is an objective I think should be supported by everyone in this country."

As police and troops stepped up security across the province, the Chief Constable of the RUC, Ronnie Flanagan, has warned that the IRA was on the offensive. "All the indications are that the IRA are planning more acts of violence," he said.

Martin McGuinness: Sinn Fein didn't kill RUC members

McGuinness tells the BBC: "People would rather I do more than condemn" (Dur: 4:20)

Sinn Fein's chief negotiator, Martin McGuinness, told the BBC that the killings should not detract from the search for peace. He said: "It is only through dialogue and negotiation that we can hope to resolve these very human tragedies." And he insisted: "Sinn Fein didn't kill the two RUC members yesterday."

But Sinn Fein still faces political isolation - there are now major doubts over the chances of a meeting between the Sinn Fein leader, Gerry Adams, and Bertie Ahern, set to be Ireland's next Prime Minister.

Meanwhile, police in Northern Ireland have confirmed that the IRA gunmen who murdered the two RUC officers were disguised. A spokesman for the RUC said that the two gunmen were wearing hair and facial disguises. He also said that detectives believe the two murdered officers were followed for a while as they patrolled the streets of Lurgan, County Armagh. The disclosure came as officers conducted house-to-house searches in the hunt for the gunmen.

Political tensions in the run-up to the marching season in Northern Ireland were stoked further when leaders of the Orange Order ruled out talks with residents in Catholic areas. The Orangemen accused the IRA of "manipulating" some of the residents groups.