(CBS/AP)-- A cargo ship was sinking after a collision on the North Sea Wednesday night and rescuers in helicopters and ships were plucking crew members from life rafts, a coast guard spokesman said.

The Dutch Coast Guard tells CBS News 13 crew members have been rescued -- 11 by helicopter and two by ship -- and 11 are still missing from the sinking car carrier. Rescuers were using infrared cameras to hunt for more survivors.

The 485-foot Baltic Ace, with a crew of 24, collided with the 440-foot container ship Corvus J around 40 miles off the coast of the southern Netherlands after dark and close to busy shipping lanes.

"We have found life rafts and the people in them are being picked up by helicopters," coast guard spokesman Peter Verburg said.

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," he said.

Verburg said the cause of the collision was not known.

"At the moment we are solely focused on getting the people to safety," he said.

A Belgian helicopter and Dutch navy frigate also were involved in the rescue operation.