As many as 100,000 people may be evacuated from their homes near Russia's border with China if the region's biggest floods for 120 years get worse, Russian media reported on Saturday.
The floods, caused by a month of unusually heavy rain, are not expected to start receding until early September, the head of Russia's hydrometeorology monitoring service told news agency Ria Novosti.
Television footage showed residents rowing boats past half-submerged houses and military vehicles dumping gravel to counter the floodwater, which has already led to the evacuation of about 170,000 people from the Amur, Khabarovsk and Jewish Autonomous regions.
"The damage is extensive, but the most significant achievement is there have been no casualties ... we cannot relax, there is still a lot of work to be done," Russian President Vladimir Putin said in a televised address.
Water has swamped huge swathes of the countryside with 400,000 hectares of agricultural land submerged, causing potential damage of more than 2 billion roubles, Putin's envoy to the region Viktor Ishaev was quoted as saying.
In 2012, flash floods killed 171 people and damaged more than 4,000 homes in southern Russia's mountainous Caucasus region.