China is intensifying diplomacy to resolve tensions over North Korea's nuclear weapons program, sending a top envoy to Washington just days after a visit to Pyongyang. China says the dispute is at a "critical" and "sensitive" stage.

China is dispatching top-level envoy, Vice Foreign Minister Dai Bingguo, to Washington for expected talks with U.S. Secretary of State Colin Powell. This, just days after Mr. Dai returned from North Korea, where he delivered a letter from Chinese President Hu Jintao.

Chinese Foreign Ministry Spokesman Kong Quan says what China is trying to do is lower the temperature and promote talks on North Korea's disputed nuclear weapons program. He called the situation on the Korean Peninsula "critical" and "sensitive."

Mr. Kong urges North Korea and the United States to exercise restraint and calmness and refrain from doing anything that might make things worse.

Beijing hosted talks in April that brought North Korea and the United States to the negotiating table with China, but those discussions ended without apparent progress.

China is reportedly offering a compromise to bridge North Korea's insistence on direct talks only with the United States and Washington's demand that Asian powers be involved.

China began this new diplomatic foray this week, after a series of conflicting reports and claims over how far North Korea has progressed in developing nuclear weapons.

North Korea has reneged on several international non-proliferation agreements and has openly admitted it is pursuing weapons, saying its needs to defend itself should the United States seek regime change in the communist nation.

More than eight months of international pressure has done little to change the situation, while North Korea says it is getting closer to building a nuclear arsenal.