A gas explosion occurred Saturday morning at a security office of the Japanese Consulate General in Shenyang, northeastern China, consulate officials said Sunday.

A Chinese guard was seriously injured. The explosion broke windows in the security office but caused no damage to the main building or other facilities, according to the officials.

The explosion was apparently set off when the guard struck a match while gas was leaking from a pipe under a nearby road, they said.

A local gas company and other entities are investigating the cause of the explosion.