At least four people were confirmed dead and 25 others were hospitalized after an explosion went off Monday morning in Xi\'an, capital of northwest China\'s Shaanxi Province. The accident happened at around 7:30 a.m. at a fast food restaurant on the first floor of Jiatian International Mansion, a commercial building in the outer Gaoxin District, a spokesman with the city\'s fire prevention bureau said. He said the dead had not been identified, and the injured were being treated at the Gaoxin Hospital and the Provincial People\'s Hospital. A doctor at Gaoxin Hospital said many were wounded on the face and head. A witness said most of the victims were passersby, including children on their way to school. A preliminary investigation indicated the explosion was caused by liquefied petroleum gas leak, a city government spokesman said. The restaurant serves a hamburger-like snack with meat between sliced pancakes, a typical Xi\'an cuisine. The explosion blast away a sign board at a nearby bus stop and damaged many cars. Broken window panes were seen two to three kilometers from the site. Xinhua reporters at the scene were unable to approach the building, as fire control authorities had cordoned the area, fearing that further blasts might cause more casualties.