Police are investigating a fatal car crash off a motorway close to Belfast in which two County Antrim teenagers died.

Lynn Anne Halliday, 18, from Gannett Way, Carrickfergus, and Jonathan Connolly, 17, from Oakwood Road in the town, died in the accident off the M5 motorway at about 0945 GMT on Tuesday.

Four others were injured including a 20-year-old woman whose condition is described as serious, and a 17-year-old girl who has head and chest injuries.

A police officer at the scene said the cause of the accident had not yet been established.

Accident scene: Car crashed through barrier

Driving conditions in the area were good at the time and it's not known why the vehicle left the carriageway.

Police Chief Inspector Mark Gilmore said the circumstances would be fully investigated.

"It's at a very early stage of our investigations - too early to come to any determination - but we haven't closed down any avenue of inquiry at present," he said.

He also appealed to motorists to do more to prevent fatal accidents.

"This problem is a joint community problem, it is not a police problem, it is a partnership issue," he said.

Mobile crane

"We ask everyone to be responsible on our roads, to understand the causes of collisions which cause serious injuries and fatalities - speed, lack of attention, failing to wear your safety belt and drink or drug driving."

The Northern Ireland Office Minister responsible for road safety, Angela Smith, said motorists had to slow down and drive more carefully.

The city bound lane of the motorway, north of Belfast, was closed for several hours after the crash which involved a people carrier.

It left the motorway, crashing through a fence onto the rocky shore of Belfast Lough, ending up on its side.

With full-time fire fighters on strike, two military Yellow Goddess fire engines attended the scene.

Death

Later, a heavy mobile crane was brought to the scene to lift the crashed vehicle onto a recovery lorry.

Terry Gorman from the ambulance service said they sent four ambulances to the crash scene.

"Unfortunately, whenever we arrived, we found there was a total of six people that had been travelling in one vehicle," Mr Gorman said.

Meanwhile, a 46-year-old man has become the 14th victim of the roads in Northern Ireland.

Tom McClurg, from Ballymacormick Drive in Bangor died on Tuesday from injuries sustained in an accident last month.

Mr McClurg was injured in the road accident at Ballydougan Road, Downpatrick on 6 December.