An explosion in a restaurant kitchen in Beijing on Friday morning has injured seven people, according to sources with the Beijing municipal fire bureau. The explosion occurred in Haidian district, west Beijing. Five fire vehicles were sent to the restaurant by the bureau. Wang Yonglu, director of the Haidian District Emergency Response Office, said that preliminary investigation indicated the explosion was caused by a liquid gas canister, and all those injured were staff of the restaurant. Windows and cooking equipments were damaged in the blast, which didn\'t cause a fire, and all the injured were hospitalized. Further investigation is under way into the exact cause of the incident.