The ministry said a cafeteria for a local government district office in Chongqing city collapsed after a suspected gas leak and explosion, trapping a total of 26 people.
Firefighters search for survivors in the rubble of the collapsed canteen in a subdistrict office.
More than 600 first responders took part in the rescue mission and officials are investigating the cause of the explosion, it added.
China has been hit by a number of gas explosions in recent years. In October, four people were killed and more than 30 injured when a blast ripped through a restaurant in the northeastern city of Shenyang.
In June, at least 12 people were killed in a huge explosion in central Hubei province.