At least four people were killed and dozens are missing after a massive suspected gas explosion partially collapsed a 10-story residential building in the Russian city of Magnitogorsk Monday morning. The blast occurred at 6 a.m. local time, when many residents would have been at home sleeping. The Russian emergencies ministry said 48 apartments were damaged after seven stories of a building collapsed. Just 52 out of the 120 people who lived in the collapsed block had been accounted for, Russian news agency TASS reported Monday, quoting the regional governor. Magnitogorsk, home to gigantic steel and iron plants, is located 1,050 miles east of Moscow.