Passers-by who tried in vain to rescue four policemen trapped in their burning 4x4 vehicle were commended for their bravery today.

Politicians at the Stormont parliament thanked those who attempted to save the men who died in the horror crash on a winding coast road in Co Down, Northern Ireland, in the early hours of yesterday.

Assembly members interrupted scheduled business to pay tribute to the four Police Service of Northern Ireland (PSNI) officers who lost their lives when their Shogun patrol vehicle lost control and crashed into a wall on a stretch of road between the harbour towns of Warrenpoint and Rostrevor.

The victims - Declan Greene, Kenny Irvine, Kevin Gorman and James Magee - all hailed from the wider Mourne area.

The MLAs' words of condolence came as eyewitness accounts of the frantic efforts to free the men from the fireball emerged.

Local taxi driver Barry McArdle arrived on the scene shortly after the 4am crash.

He said people were already trying to break the windows and he made his own attempt to smash the glass with a fire extinguisher.

"I saw people beating the window with metal bars or bats," he said.

"I hit the window maybe three, four times with the fire extinguisher but the windows were not moving, it was just having no effect and the flames were getting the better of us."

The PSNI has launched an investigation into the circumstances of the crash.

A 'black box' recorder in the vehicle will be key to uncovering what happened and police said they will probe unconfirmed reports the blaze set-off ammunition in the car.

The four policemen were all aged in their mid-20s to mid-30s and it is understood three had young children.

Two were full-time officers while their colleagues were part-time community officers.

One of the victims, Declan Greene lost three members of his family in the Tullymurray Lass fishing tragedy off the Co Down coast six years ago.

At the scene of yesterday's crash flowers and other tributes were laid today in memory of the officers.

A pair of baby's boots carried the words 'Daddy's Girl', while a Liverpool football club jersey bore the message, 'My Daddy, My Hero'.

All of South Down's six Assembly members joined together to pass on their sympathies to the officers' families.

Condolences were also expressed to the relatives of the six other people killed in separate road crashes in the island of Ireland over the weekend.

Sinn Fein's Willie Clarke said his thoughts were not only with the bereaved, but also with the emergency services and members of the public who had tried to help.

"These young officers were serving the community from which they came," he said.

"These officers were at the forefront of the new beginning to policing (in Northern Ireland) and for them to lose their lives at the mouth of Christmas adds to the loss. Children have lost their fathers, wives have lost partners and mothers and fathers have lost sons."

Fellow Sinn Fein member and Education Minister Caitriona Ruane said she felt for all the families who had lost loved ones.

"This is going to be a very difficult Christmas for all their families and our party shares and sympathises with those families," she said.

Democratic Unionist Jim Wells said a dreadful cloud of grief hung over the whole of South Down.

"This dreadful tragedy has once again reminded us of the risk taken by dedicated police officers who do so much to protect our community," he said.

SDLP Social Development Minister Margaret Ritchie said the community was shrouded in gloom.

"I know that the wider constituency of South Down and the people of South Down will stand shoulder to shoulder with the bereaved in their grief and their loss," she said.

"I want to offer my sympathy, my condolences and offer my support to the bereaved in their tragic loss and also to the PSNI because they've lost four very fine young men who were out doing their duty providing protection and safety to the wider community."

Ms Ritchie's party colleague PJ Bradley also paid his respects.

"I ask that this Assembly joins with my South Down colleagues and I in paying tribute to the four young policemen that died," he said.

"Declan Greene, Kenny Irvine, Kevin Gorman and James Magee - all of whom died on duty and serving the South Down public in the late hours, when most of us were in bed they were working for the good of the community."

Ulster Unionist John McCallister said his thoughts were with all those who had died on the roads over the weekend.

"Turning to the tragedy that the police service has suffered," he added. "(These were) four colleagues, four young men serving all of our community with distinction and (I) extend to them and their families, friends and colleagues and to the Chief Constable our sincere sympathy and condolence and assure them that on my behalf and behalf of my party colleagues that they are very much in our thoughts and prayers at this difficult time."

Mr McArdle said he and others finally had to abandon their efforts to rescue the men when the flames got too intense.

"I heard someone saying stand back, or run," he told Radio Ulster.

"I just remember at one point the four or five people round the jeep just ran at the same time. There was only so much we could do."

The weekend deaths brings to 98 the number of people killed in road accidents in Northern Ireland since the beginning of the year.

In the wake of the crash, Chief Constable Sir Hugh Orde said the PSNI had suffered a terrible blow.

"The police family has lost four fine police officers in what are deeply tragic circumstances and our heartfelt condolences go out to their families," he said.

"Our thoughts are with them as they struggle to come to terms with their loss."