Beijing ? The United States said Tuesday that it was sending experts to help China cope with a river-borne toxic spill that is approaching Russia’s Far East, while Beijing promised to work closely with Moscow to limit the damage.

Clark Randt, the U.S. ambassador to China, said the communist government had accepted the offer of an Environmental Protection Agency assessment team that would suggest ways to remedy effects of the 90-mile chemical slick.

A Chinese Foreign Ministry spokesman said Tuesday that Premier Wen Jiabao had written a letter to his Russian counterpart that “reaffirmed China’s readiness to further cooperate with Russia to deal with the aftermath of the pollution.”