Story highlights

The blast was at a commercial building in the city of Xi'an, Xinhua reports

At least 31 are injured, a local fire spokesman says

Windows were broken several kilometers away

CNN  — 

A huge explosion rocked a commercial building Monday morning in central China, killing at least seven people and injuring 31, state media said.

The incident occurred around 7:30 a.m. at Jiatian International Mansion, which is in Xi’an, the capital of Shaanxi province, a city fire prevention bureau spokesman told Xinhua.

The blast led to broken windows 2 to 3 kilometers (1 to 2 miles) from the site, with many cars damaged and a sign over a bus stop blown away closer to the site.

The spokesman characterized the explosion as an “accident,” according to the state-run news organization.

Authorities sealed off the area, guarding against possibly more explosions and casualties, according to Xinhua reporters on the scene.