A Dutch cargo ship has sunk following a collision with a tanker carrying liquid gas off the Belgian coast near Zeebrugge.

It is not yet clear why the Flinterstar collided with the Al Oraiq, which was sailing under the Marshall Islands flag. Twelve crew were knocked into the sea during the incident but all were rescued safely, broadcaster Nos said.

According to Belgian officials, the 130-metre Flinterstar was not carrying any dangerous cargo at the time. ‘There are traces of oil but not enough to pose any danger,’ Nos quoted the official as saying.

Flinter’s director Bart Otto told ANP the Flinterstar is on a sandback ‘with water up to the deck’. He said he was happy the crew had been rescued safely, although several have been taken to hospital.

The tanker has been towed to Zeebrugge for repairs but is not thought to be leaking, news agency ANP said.

A Dutch salvage vessel is on its way to the accident location. Shipping in the western part of the Westerschelde estuary has been disrupted, Nos said.