The prime minister has condemned an IRA offer to shoot suspects involved in a Belfast murder.

Speaking in the Commons on Wednesday Tony Blair said the statement "frankly defies any description".

Republicans have been under intense pressure to hand over men suspected of being behind the January stabbing of Robert McCartney in a Belfast bar.

Although the IRA does not recognise the Police Service of Northern Ireland as legitimate, the paramilitary group offered to take justice into their own hands on Tuesday by issuing punishment shootings.

However the move was rejected by the McCartney family, which has been at the forefront of a community uprising against the murder.

Labour MP Kevin McNamara said there was "horror and contempt" for the IRA's announcement.

Responding, Blair aid the MP's condemnation was "telling". "The IRA statement yesterday, frankly, defies any description," he told the Commons.

"It was quite an extraordinary thing to say. It cannot be in any shape or form justified.

"There is no way we can make any progress in Northern Ireland that includes Sinn Fein unless we have a complete and total end to violence of whatever kind."

Democratic Unionist leader Ian Paisley said the prime minister's words were "useless" without action against the IRA.

Earlier Eddie McGrady, an MP for the nationalist SDLP, said: "This appalling proposal is an extremely dangerous slide into anarchy and is a threat to the entire community of Northern Ireland."

And even Sinn Fein's Martin McGuinness said he was surprised by the IRA statement.

He said he thought it would have been "very unfortunate" if the organisation had shot the alleged killers.

"I think the difficulty about this particular sentence in the statement is it takes away from what I think is an awful lot of positive stuff," McGuinness said.