Baku, July 21, AZERTAC Four people died and 13 others were injured in a gas explosion that damaged part of an apartment building in north China's Tianjin Municipality, local government said Wednesday, according to Xinhua.The explosion took place at around 7:15 a.m. on Tuesday in Beichen District, trapping a number of residents and damaging part of three stories of the building. Search and rescue efforts ended after the last three people were found in the wee hours of Wednesday.Four people died despite emergency treatment. The injuries sustained by 13 others are not life-threatening, according to the publicity department of the district government.So far, power and water supplies have resumed and gas supply has also been basically restored in the neighborhood affected by the explosion. A further investigation into the explosion is underway.