China shipped missile-launch vehicles to North Korea last year in breach of UN resolutions but was never rebuked because the U.S. did not want to embarrass Beijing, a Japanese newspaper said Wednesday, June 13, according to AFP.

Beijing denied the report, which is based on Japanese government sources and is the most strident of recent claims that China has been involved in helping to arm its wayward ally, after earlier allegations Beijing supplied technology.

Four giant trucks capable of transporting and launching ballistic missiles were exported by a Chinese firm last August, the leading Asahi Shimbun said.

The vehicles were likely those on display at the huge military display in April marking the centenary of the birth of the state's founder Kim Il-Sung, the Asahi said.

The sale of weapons systems to Pyongyang is banned under UN Security Council resolutions aimed at containing the hermit state's nuclear ambitions.

But at Washington's urging, Tokyo and Seoul have avoided confronting Beijing in a bid to keep North Korea's patron onside in the international effort to tamp down tensions on the peninsula, the paper reported.

Top Japanese government spokesman Osamu Fujimura declined to confirm the report, saying it was "a matter of intelligence".

Asked about the claim, Chinese foreign ministry spokesman Liu Weimin said in Beijing: "China has been strictly implementing relevant Security Council resolutions and its own laws and regulations on non-proliferation export control. Chinese companies did not export items that are banned by relevant Security Council resolutions or Chinese laws and regulations."