China and Russia are discussing plans to set up a hotline so Chinese officials can inform Moscow about a toxic chemical spill that is flowing toward Russian territory.

Authorities in Russia's far eastern Khabarovsk region Thursday are on alert as heavily contaminated waters from China head downriver.

Chinese authorities have already had to close the water mains in Harbin, one of China's largest northeastern cities, because of a huge slick of toxic benzene in the Songhua River.

Scientists say even small amounts of the industrial solvent can cause mouth ulcers, and larger quantities can cause leukemia.

Facing criticism, Chinese officials have promised to take measures to monitor pollutants.

The contamination stems from a chemical plant explosion that spilled toxic compounds into the Songhua River on November 13.

Some information for this report provided by AP and Reuters.