Sinn Féin and the Democratic Unionist Party come in for criticism in an end-of-year review of the peace process by US special envoy for Northern Ireland Mitchell Reiss.
"Sinn Féin is the only political party in Europe that does not support policing," he writes in the weekly Irish Echo, published in New York.
Outlining the Bush administration's attitude to the party's continued refusal to join the Policing Board, he writes: "We think Sinn Féin has a responsibility to tell its constituents they should co-operate with the police - without fear of retribution - whenever dissidents, thugs and degenerates terrorise their communities.
"Gerry Adams and other Sinn Féin leaders have met repeatedly with Hugh Orde, the chief constable, and other PSNI officials. If they can talk with the PSNI, why can't ordinary republicans and nationalists? By denying republicans and nationalists proper policing and justice, Sinn Féin has condemned them to a ghettoised existence."
He continues: "Now we all recognise that policing is not perfect in Northern Ireland. It isn't perfect in any city. But the undisputed fact, acknowledged by even Sinn Féin, is that there has been tremendous progress in recent years. The PSNI is simply not the same as the old RUC."
On the position of unionists, he writes that, "Some DUP politicians have claimed recently that it will be 10 years before they join with Sinn Féin - clearly not a very constructive approach."
He says the US, British and Irish governments "have spent so much time and effort focusing on Sinn Féin and the IRA that we haven't devoted as much attention to the DUP ... That needs to change."
Meanwhile British government sources, speaking on condition of anonymity, have disputed the claim by Minister for Foreign Affairs Dermot Ahern that Dublin was not informed in advance about the inclusion of security force personnel in legislation providing de facto amnesty for paramilitary fugitives or on-the-runs.
Interviewed on RTÉ Radio's News at One yesterday, Mr Ahern said: "We weren't informed about the inclusion of security services in their legislation until the legislation came out."
Pressed on the issue, he added: "We hadn't been informed at all in relation to their intention to include security services."
He confirmed that if the British legislation were now withdrawn in the face of multiparty opposition, Dublin would also drop its own proposals for pardons. "If British legislation doesn't go ahead, the proposals that we were enunciating wouldn't go ahead either," Mr Ahern said.
British government sources told The Irish Times last night: "We did discuss the whole shape of the scheme with the Irish Government but it's really a matter for them to answer questions on what they knew and didn't know."
Ulster Unionist Party leader Sir Reg Empey has called on Northern Ireland Secretary Peter Hain to urge his cabinet colleagues to drop the fugitives Bill. "Last night Sinn Féin indicated that they no longer supported the legislation. This now leaves not one party in Northern Ireland in favour of it, albeit for differing reasons," the UUP leader said.
Minister for Justice Michael McDowell said yesterday in Longford: "As far as I know, the principles of the legislation that were put in place in the House of Commons were agreed with the Sinn Féin leadership. And they are now repudiating something in public which they agreed to in private, because of political pressure."
This morning Sir Hugh Orde will discuss recent security developments in a meeting with Taoiseach Bertie Ahern as well as the Ministers for Foreign Affairs and Justice at Government Buildings in Dublin.