From Reuters via the New York Times:

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North Korea’s test firing of a volley of missiles in July has disappointed its traditional ally China, U.S. Assistant Secretary of State Christopher Hill said in Beijing on Tuesday. [Full Text]

See also Reuters’ U.S., China Mull Warning N.Korea Against Nuclear Test:

China and the United States have discussed warning North Korea against conducting a nuclear test, U.S. Assistant Secretary of State Christopher Hill said in Beijing on Wednesday.

“We talked about the need to make very clear to the DPRK that this would a very, very unwelcome development,” Hill told reporters after meeting Wu Dawei, China’s chief diplomat in charge of negotiations with North Korea.

Also AP’s longer U.S. Envoy Frustrated With North Korea:

The chief American negotiator on North Korea’s nuclear program expressed frustration Tuesday with Pyongyang‘s refusal to return to six-nation talks amid concerns the regime might be preparing a nuclear test.

China, meanwhile, denied that arrangements were under way for a visit by the North’s reclusive leader, Kim Jong Il, despite media reports that his special train had arrived in a city on the Korean-Chinese border.