HANGZHOU, Jan. 28 -- Four people have been killed and three others are missing after an Indian oil tanker exploded and caught fire at a shipyard in east China's Zhejiang Province on Tuesday.

Smoke was detected followed by the explosion at 7:30 a.m., when seven workers were repairing the unloaded tanker, which has an oil load capacity of 50,000 tonnes, at the Haizhou Shipyard in Daishan County in the city of Zhoushan, said a spokesman with the city government.

As of noon time, the fire had been put out and rescuers were still searching for the three missing people, said the spokesman.

The identities of the victims are not available yet.

The cause of the accident is under investigation.