A gas cylinder exploded at a restaurant in downtown Beijing early on Friday, injuring three employees and an unknown number of passers-by, police and the state Xinhua news agency reported.
Those hurt in the blast in the Xinjiekou area of the Chinese capital were taken to hospital, but their injuries were not life-threatening, Xinhua said, citing unnamed sources.
The agency said the number of passers-by injured was not immediately known.
"According to the initial investigation, the explosion was an accident," an area policewoman told AFP.
Xinhua, quoting a witness surnamed Qiao, said the restaurant had collapsed following the explosion.
The blast comes amid a security clampdown in the capital ahead of sensitive October 1 celebrations marking the 60th anniversary of the founding of communist China.
The Xinjiekou area is located northwest of Tiananmen Square, the focus of the National Day festivities.