Washington ? The U.S. on Sunday pressed China to enforce the U.N. punishment against North Korea and use economic leverage to persuade the communist ally to renounce its nuclear weapons program and rejoin international disarmament talks.

The chief U.S. diplomat readied for talks in Asia, aware of concerns that the Security Council’s resolution might enflame tensions among countries already on edge from North Korea’s claimed nuclear test Oct. 9.

Already, sharp divisions have arisen over enforcing the resolution, approved unanimously Saturday. China, which voted for the penalties, is balking at cargo inspections to prevent trafficking of certain banned weapons and technology.

“I’m quite certain that China is going to live up to its responsibilities,” said Secretary of State Condoleezza Rice, adding she was willing to have “conversations” during her trip on how best to enforce the resolution.

Washington’s U.N. ambassador portrayed this month’s detonation as a public humiliation for China, which has urged patient diplomacy to halt Pyongyang’s nuclear program. China shares a long border with North Korea and is the North’s chief ally and supplier of crucial shipments of food and energy aid. An air sampling taken after the blast detected radioactivity consistent with an atomic explosion, Bush administration and congressional officials said Friday.

If China were to cut that support, John Bolton said, it “would be powerfully persuasive in Pyongyang,” the North’s capital. “They’ve not yet been willing to do it. I think that China has a heavy responsibility here.”

He said North Korea’s apparent nuclear test “had to have been humiliating to China. … And I think we’re still seeing that play out.”

Rice, who joined Bolton in making the rounds of the Sunday talk shows in Washington, leaves Tuesday to consult with Asian allies about the resolution. “I understand that people are concerned about how it might work so it doesn’t enhance tensions in the region, and we’re perfectly willing to have those conversations,” Rice said.

She said an embargo against North Korea “is a very important tool that the international community can use. But we’ll want to use it in a way that does not enhance the possibility for open conflict.”

Japan and Australia have pledged immediate enforcement of the penalties and said they were considering harsher measures on their own. South Korea, which has taken a conciliatory approach to the North and has provided its neighbor with aid, said it would abide by the resolution’s terms but did not say how.

The U.S.-sponsored resolution demands North Korea eliminate nuclear weapons but rules out military action against the country, as the Russians and Chinese demanded to gain their approval.