Explosion hits Xi'an office building, casualties unknown

An explosion hit an office building in Xi'an, capital of northwest China's Shaanxi province, on Wednesday afternoon. Casualties are not yet known.

The blast occurred around 5 p.m. within a film animation industrial park in Beilin district, sources with the city's firefighting authorities said.

Some of the building's walls have collapsed, according to the sources.

Pictures circulated on the Internet showed that the blast ripped through the second floor of the west-wing of the 10-story building, with heavy smoke billowing into the sky. Blazes could be seen on the second floor as of 5:10 p.m.

"The whole second floor is unrecognizable. It's on fire now," said a Sina Weibo microblogger, adding he was pressed to the ground by the shock wave of the explosion.

A dozen cars parked near the building were damaged, the pictures show.

Firefighters and medical workers have arrived at the scene, which has been cordoned off.