An anti-British gang opposed to Northern Ireland's peace talks claimed responsibility Saturday for the shooting death of a retired policeman. It made no at-tempt to justify the killing.

In a short statement to the BBC in Belfast, the outlawed Irish National Liberation Army said it had killed Cyril Stewart, 52, who retired last year after suffering a heart attack.The INLA gave no explanation for Friday's shooting outside a supermarket in Armagh, 40 miles southwest of Belfast. Critics said it was the latest effort by extremists to cause peace talks to unravel.

The talks among eight parties resume Monday. They face an April 9 deadline to reach a settlement acceptable to the north's pro-British Protestant majority, which wants strong government within Northern Ireland, and to a Catholic minority determined to build ties with the rest of Ireland.

The British and Irish prime ministers, Tony Blair and Bertie Ahern, discussed the prospects for achieving a compromise in a 20-minute telephone conversation.

Afterward, Blair's spokesman said the British leader would meet several Northern Ireland party leaders in London.

The INLA, a maverick critic of the larger IRA that shares its aim of ending British rule, opposes the IRA truce on the grounds that the talks are unlikely to sever Northern Ireland's links with Britain.

Mitchel McLaughlin, chairman of the IRA-allied Sinn Fein party, said he regretted the killing. It was designed, he said, to make the search for agreement harder.

"Unfortunately there are those who are outside the peace process and who believe it cannot work. Now let's prove them wrong."

Politicians linked with Northern Ireland's major pro-British paramilitary groups appealed against retaliation.