MOSCOW, July 24 (Reuters) - Emergency sirens sounded in the southern Russian region of Sochi overnight after rivers burst their banks in heavy rain for a second time this month and flooding closed a motorway. The sirens, heard in areas near the city of Sochi, which hosted the 2014 Winter Olympics, were a warning for residents but evacuation was not planned at this time, the emergencies ministry was cited by the TASS news agency as saying. Earlier this month, heavy rains caused severe flooding in the same area, with roads turning into rivers for several days. On Friday, floods also hit an area of Russia"s Far East, damaging a bridge on the Trans-Siberian railway line partially suspending rail traffic on a transportation artery that is crucial for Russia"s economy. read more