According to Yonhap News Agency, South Korea’s official news agency, China has “suspended government exchanges with North Korea.” Via Heejin Koo and Kyung Bok Cho of Bloomberg:

China suspended government exchanges with North Korea after Kim Jong-Il’s regime last week tested a nuclear device and fired short-range missiles, Yonhap News said.

China has halted plans to send officials to North Korea and won’t accept visits from there either, Yonhap said today, citing unidentified diplomatic sources in Beijing. China’s foreign ministry didn’t respond to a faxed request for comment. South Korean government spokesman Lim Jung Taek said he couldn’t confirm or deny the report.

The move, if confirmed, would be the strongest reaction yet to North Korea’s actions by its biggest ally and trading partner. China accounts for almost three-fourths of North Korea’s foreign trade, and can cut off shipments to the impoverished country of food, fuel and luxury goods.

Elizabeth Bumiller reports for the New York Times on U.S. Defense Secretary Robert Gates’s Asia trip:

Mr. Gates met on Saturday with the highest-ranking Chinese official at the conference, Lt. Gen. Ma Xiaotian, the deputy chief of the general staff of the People’s Liberation Army. American defense officials said after the meeting that China, which has been reluctant to take tough action against North Korea, clearly viewed the nuclear test seriously.

Update:  Chris Buckley reports for Reuters on how China’s condemnation of the nuclear test is spreading to Chinese media, and how this may be different from Beijing’s previous stance with North Korea:

The top item on the Chinese website of Beijing’s embassy in Pyongyang is a condemnation of North Korea’s nuclear test.

That, and a recent blast of blunt criticism of North Korea in China’s state-run press, suggest the rancour that officials feel towards their communist neighbour — anger likely to bring Beijing behind a U.N. resolution condemning the May 25 test and threatening fresh sanctions.
On Monday, a commentary in the same paper called North Korea a “strategic burden” for China. Not the kind of language the government would have allowed earlier this year, when the focus was on celebrating 60 years of ties with the Communist North.

Zhan Debin, an expert on Korea at Fudan University in Shanghai, wrote in the paper that the Chinese government could soon be pushed to abandon its usual reticence.