XI'AN • A powerful explosion in a prefabricated house ripped through a town in China's northwest Shaanxi province yesterday, leaving at least seven dead and 94 hospitalised, the local authorities have said.

"I was at home when I heard a loud boom. It felt like the house was about to be flipped," a local resident told reporters.

An initial investigation indicated that the makeshift house had been built inside a residential compound, the Xinhua news agency reported.

It remains unclear what caused the explosion in the coal-mining town of Xinmin in Fugu county. But local newspaper Huashang reported on its website that the blast had something to do with explosives hidden in the basement of the building.

The blast reportedly left a 5m-wide and 4m-deep crater next to a hospital, part of which was blown off. Some other buildings nearby were also damaged by the impact.

Of the 94 people warded for injuries, four are in intensive care.

In August, a blast at a power plant in Dangyang city, central Hubei, killed at least 21 people on the eve of the first anniversary marking massive chemical explosions in the Chinese port city of Tianjin. The blasts in north-east China killed more than 170 people.