An explosion occurred in an apartment building in Russia's Ural Mountains Monday, The Associated Press quoted emergency officials as saying, and the Interfax news agency reported that the blast was caused by gas and that several people were hospitalized. A police official said people remained under the rubble and children's cries could be heard after the explosion in a three-story building in the Sverdlovsk region city of Kushva, Interfax reported. A regional emergency department official said an explosion occurred but had no information about the cause or casualties.