An oil depot exploded in northeast China's Liaoning province Tuesday, local authorities said.

The explosion occurred at 4:30 p.m. in the Yuhong district of the provincial capital of Shenyang, shattering windows at a distance of 200 meters and resulting in a massive cloud of smoke, witnesses said.

Firefighters have arrived at the scene of the explosion. The area was still covered in smoke as of 6:10 p.m.

The cause of the explosion and number of casualties, if any, are unknown.