A cargo ship sank off the Dutch coast on Wednesday night after it collided with another vessel. Four crew members died, while seven went missing in the icy waters of the North Sea, rescuers said.

"We can confirm that four bodies have been found, along with 13 people rescued alive," Coast Guard spokesman, Marcel Oldenburger, told the Associated Press.

The sinking of the ship was followed up by a massive air and sea rescue operation involving several helicopters, two navy patrol ships and even on of the ships involved in the collision.

The 148-meter (485-foot) Baltic Ace collided with the 134-meter (440-foot) container ship Corvus J in darkness near busy shipping lanes some 65 kilometers (40 miles) off the coast of the southern Netherlands, according to AP. The Baltic Ace, carrying a cargo of cars, had a crew of 24, which was forced to abandon ship as it sank quickly.

A statement, cited by the AP, indicates that by approximately 10 p.m., 11 crew members had been rescued by helicopters and two more ships.

The rescue operation was called off at about 2 a.m. before Coast Guard officials said they would decide at daylight whether to continue the search.

"We still hope to find them," Kees Brinkman, a spokesman for 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 Defense Ministry said in a statement, obtained by the AP, that two navy patrol ships were aiding the search. "Helicopters are trying, in (strong wind) and high waves to bring the people to safety," the ministry said.

The coast guard spokesman said the cause of the collision was not known. "At the moment we are solely focused on getting the people to safety," he said.

Four of the survivors were being flown to a hospital in Rotterdam and seven to an airbase 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 in Scotland to Antwerp, Belgium, the AP said.