Seven sailors missing in the icy North Sea after a cargo ship collided with another vessel and sank off the Dutch coast are almost certainly dead, rescuers said today.

A massive air and sea rescue operation involving several helicopters, two navy patrol ships and even one of the ships involved in yesterday's collision, which killed four cargo ship crew members, was called off at about 2am.

Coastguard chiefs said they would decide at daylight whether to continue the search.

Coastguard spokesman Peter Verburg said "the chance of finding anyone alive now is virtually zero".

"We are doing all we can, but time is overtaking us," he said.

Four bodies were recovered and 13 people rescued.

The 485ft Baltic Ace collided with the 440ft container ship Corvus J, heading from Scotland to Belgium, in darkness near busy shipping lanes 40 miles off the coast of the southern Netherlands. The Baltic Ace, carrying a cargo of cars, had a crew of 24 which was forced to abandon ship as it sank quickly.

By around 10pm (9pm GMT), 11 crew members had been rescued by helicopters and two more by ships, the coastguard said. Rescuers were using infrared cameras to hunt for more survivors.

"We still hope to find them," Kees Brinkman, a spokesman for the rescuers, told Dutch television nearly four hours after the collision. But, he added: "Their chances of survival are shrinking" if they are in the water.

The Dutch Defence Ministry said two navy patrol ships were aiding the search. "Helicopters are trying, in (strong wind) and high waves to bring the people to safety," it said.

Mr Verburg said the 12-man crew of the Corvus J was still on board the ship, which was helping in the rescue operation. "It is badly damaged, but not in danger of sinking," Mr Verburg said.

Four of the survivors were being flown to a hospital in Rotterdam and seven to an air base in Belgium.

The Baltic Ace, sailing under a Bahamas flag, was heading from the Belgian port of Zeebrugge to Kotka in Finland, and the Cyprus-registered Corvus J was on its way from Grangemouth, Scotland to Antwerp.