BEIJING  - China Sunday said it was concerned at North Korea's plans to launch a rocket later this month, state media reported."China ... expressed its concern about the satellite launch plan of the Democratic People's Republic of Korea, saying it hopes relevant parties can act in a way that is more conducive to the stability of the Korean peninsula," Xinhua news agency said.The Xinhua report, which did not give a source for the statement, came a day after North Korea announced that its second long-range rocket launch this year will take place between December 10 and 22. The United States and its key Asian military allies South Korea and Japan have condemned the planned launch as a disguised ballistic missile test that violates UN resolutions triggered by Pyongyang's two nuclear tests in 2006 and 2009.As in April, North Korea said the launch would be a purely "peaceful, scientific" mission aimed at placing a polar-orbiting earth observation satellite into orbit.China is North Korea's sole major ally, and Pyongyang has increased its reliance on its neighbour in recent years as sanctions over its missile and nuclear programmes strangled its ability to secure international credit and foreign trade.