The victim, a van driver in his mid-30s, was found with gunshot wounds lying in a street in north Belfast after midnight on Saturday morning.

Mark Devenport: "Mr Service was shot twice in the head and three times in the back"

The man - named locally as Brian Service - had been shot several times in the head and back.

He died later in hospital.

The shooting occured in an area where Catholic and Protestant neighbours meet.

'Chosen at random'

BBC Ireland Correspondent Mark Devenport: "Locals say man was targeted due to his religion"

Sinn Fein said it believed the murder was an attempt to heighten tensions at a critical time in the peace process.

Sinn Fein's Mitchel McLaughlin appealed for republicans to stay calm. "I believe that a loyalist organisation was involved. I would appeal for nationalists in north Belfast to be vigilant," he said.

And Ken Maginnis, the Ulster Unionist's security spokesman, said: "Whatever the motive for this killing, which at first sight appears to be sectarian, there can be no excuse."

The dead man was described as an ordinary working man who came from a respectable family and had no paramilitary or criminal connections.

Alban Maginness, SDLP Assembly member for north Belfast, who knew the family, said: "This was a victim who seemed to have been picked out completely at random and then killed very deliberately and with precision.

"It is reminiscent of the sectarian killings that have characterised north Belfast. The whole thing is very sinister."

Identity not released

A green Honda car stolen on Friday was found near the scene and police said they were investigating a possible link with the attack.

An RUC spokesman said: "A murder inquiry is under way and we are investigating a motive for the attack, but at this stage it is too early to speculate."

The dead man's identity has not been released.

Prisoners freed

Meanwhile, Irish Prime Minister Bertie Ahern is to travel to Stormont on Monday in a bid to advance the Northern Ireland peace process.

The announcement comes as the deadlock over arms decommissioning continues to delay implementation of the Good Friday Agreement.

In Dublin, four more IRA prisoners are being freed from the high-security Portlaoise jail as part of the peace accord.

The four men are the last IRA members imprisoned for weapons and explosive offences on the southern side of the Irish border to be released.