An Indian oil tanker being repaired at a shipyard in eastern China exploded and caught fire Tuesday, killing seven Chinese workers, Chinese state media said.

The workers were repairing the ship when the explosion occurred at Haizhou Shipyard in the port city of Zhoushan, the official Xinhua News Agency said. There was no report of an oil spill.

Workers at the shipyard, reached over the phone, confirmed that the oil tanker was docked there but were unable to provide any other information.

State-run China Central Television said an open flame triggered the blast but did not provide further details. Xinhua said the cause was under investigation.

The ship has a capacity of 50,000 tons of oil, Xinhua said.