The Amur River, which marks the border between China and Russia, has experienced its worst flooding in a century, cutting off roads to some areas, Chinese state media said on Monday.
The Amur, which China knows as the Heilong River, has risen since mid-August with some middle and lower sections reaching their highest levels since records began in 1896, the Xinhua news agency said.
On Saturday, one station on the river measured a record high water level of 50.62 metres, 1.31 metres more than the previous high in 1984, it said.
Another station registered a high of 43.37 metres, also surpassing a 1984 record, Xinhua said.
Floods had cut off roads leading to Fuyuan county, which has a population of 170,000 people and sits across the border from the Russian Far East city of Khabarovsk, the report said.
Authorities in the northeastern province of Heilongjiang, on the Chinese side of the river, have ordered local governments to take steps to prevent flooding by reinforcing and inspecting flood walls, it said.