In this handout photo released by the Nizhny Tagil Head Press Office, emergency specialists work at the site of a damaged apartment block where two sections of a five-storey building collapsed following a suspected gas explosion in Nizhny Tagil, Sverdlovsk region, Russia. According to latest reports, at least twelve people were injured, including six children. Two adults were hospitalised. Three people remain unaccounted for while a search and rescue operation is under way. Editorial use only, no archive, no commercial use.