Protestant extremists have claimed responsibility for the drive-by murder of leading Northern Ireland journalist Martin O'Hagan, gunned down in front of his wife as they walked near their home.

The killing - the first of a reporter in more than 30 years of strife in Northern Ireland - sent shockwaves across the province and was condemned by British and Irish government ministers and politicians in its Protestant and Roman Catholic communities.

O'Hagan, of the Dublin-based Sunday World newspaper, was shot from a passing car late on Friday as he walked home with his wife from a pub in Lurgan, County Armagh, 40 km from Belfast.

The Red Hand Defenders (RHD), a cover name used by pro-British "loyalist" gunmen, said in a statement to the BBC in Belfast that it had shot O'Hagan for "crimes against the loyalist people".

O'Hagan, 51, had been an investigative reporter on the Northern Ireland edition of the mass circulation tabloid for several years. It specialises in exposes of pro-Irish republican and pro-British guerrilla groups, and drug barons.

Police said a car believed to have been used in the attack was found burned out a short time later.

Britain's Northern Ireland Secretary John Reid denounced the killing as barbaric.

"It is also a very, very dangerous indication of what happens when violence tries to suppress democracy - because here we had someone who was involved in exposing a great deal of crime and a great deal of corruption," he told reporters.

O'Hagan's wife was uninjured in the attack, but was suffering severe shock, police said.

O'Hagan, a father of three daughters - one of whom is due to be married within weeks - had received death threats in the past. He had been threatened by the Loyalist Volunteer Force (LVF), media reports said.

"I am angry, I am sore. My heart's aching and breaking for him and that wee family in there," Jim McDowell, the paper's Northern Ireland editor told reporters at the scene.

"What the hell do they think they've achieved?" he added.

Further strains on peace drive

Politicians condemned the attack. David Trimble, the province's former first minister and leader of the main Protestant political party, said he was shocked and appalled by "this cowardly act".

Irish Foreign Minister Brian Cowen described the killing as deeply shocking and cynical.

"It was an attack on a dedicated and hardworking journalist and it also represented an assault on one of the fundamental principles of any democratic society - an independent and unfettered media," he said in a statement.

Those who carried out the attack had nothing to offer the people of Northern Ireland except fear and silence, he added.

The RHD tag has been used as a flag of convenience by elements of the powerful Ulster Defence Association (UDA) and the LVF, according to security sources.

Both groups were involved in sectarian strife which raged for 30 years until subsiding in truces by the province's major rival armed factions as a fragile peace process developed into the landmark 1998 Good Friday peace pact.

The shooting put further strains on the province's peace drive. Just hours earlier Britain stopped short of declaring the UDA's ceasefire over after the group vowed to call off nightly street violence that had erupted in Belfast.

The market town of Lurgan is just five miles from Portadown, a stronghold of the LVF.

O'Hagan was the second Sunday World journalist to be attacked. A colleague was shot and seriously wounded by loyalists in the mid-1970s.

© Reuters