Dutch sea rescue services launched a major operation Wednesday to save 24 sailors after their ship sank following a collision with another in a busy North Sea shipping lane, a coast guard spokesman said. \"Three helicopters are on the scene as well as two rescue ships and a number of other craft to pick up 24 crew members of the Baltic Ace,\" Peter Verburg of the Dutch coast guard told AFP. He said the crew launched life rafts after the 23,000-tonne Bahaman-registered Baltic Ace, a car carrier, and the Cypriot-registered Corvus J, a container ship, collided around 7:15 pm (1815 GMT) about 100 kilometres (60 miles) from Rotterdam and 65 kilometres off the southern Dutch coast. It was unknown if there were any injuries. The Baltic Ace was under way from Zeebrugge in Belgium to Kotka in Finland and the Corvus J from Grangemouth in Scotland to Antwerp in Belgium, according to shipping tracker website MarineTraffic.com. \"At this stage we don\'t know what caused the accident,\" Verburg said, adding: \"Our first priority right now is the safety of the 24 crew members.\" The shipping lane where the accident happened is one of the busiest in the North Sea and an important passing point for ships sailing into the Rotterdam port, Europe\'s largest and the fifth-largest in the world, Dutch media reported. Rotterdam port spokesman Sjaak Poppe told AFP the collision would not affect shipping in and out of the port.