By Chris Buckley
BEIJING (Reuters) - Chinese Premier Wen Jiabao told his Japanese counterpart Naoto Kan on Tuesday he was concerned about the release of radiation into the ocean and urged Tokyo to take "very seriously" the possible impact on neighboring countries.
The comments from the Chinese government leader were the sharpest sign yet that Beijing is worried about Japan's escalating nuclear crisis, although Wen also stressed hopes for better ties with Tokyo, after bouts of friction last year.
"The Chinese government and people express their concern about this, and ask that the Japanese government attach high importance to the impact of this matter on the marine environment and especially surrounding countries," Wen told Kan in a telephone call, according to a summary of the discussion on the Chinese Foreign Ministry website (www.mfa.gov.cn).
Wen told Kan that his government should "strictly abide by the relevant international law and take effective prevention and control measures, as well as swiftly, comprehensively and accurately reporting the situation to China."
Japan's Prime Minister Kan expressed regret about the nuclear accident and told Wen that Japan would indeed provide swift and accurate information, said the foreign ministry account.
But Wen also stressed Beijing's hopes for steadier ties with Tokyo. China has been Japan's biggest trading partner since 2009.
Last year, Asia's two largest economies faced off in a maritime territorial dispute that intensified longstanding mutual suspicion over disputed undersea gas reserves, military plans, and Japan's brutal occupation of China before and during World War Two.
Chinese officials have sent aid and rescue teams to help Japan after its earthquake and tsunami which triggered the nuclear crisis, underscoring hopes that the disaster may help heal ties.
"We are willing to strengthen cooperation with Japan for disaster relief and post-disaster reconstruction," Wen told Kan, adding that he wanted to "promote healthy and stable Sino-Japanese relations."
(Reporting by Chris Buckley and Simon Rabinovitch; Writing by Sui-Lee Wee; Editing by Andrew Marshall)