BANDAR SERI BEGAWAN, Brunei Secretary of State John Kerry said on Monday China's Foreign Minister Wang Yi assured him that Beijing had been "very firm" with North Korea on its need to end its nuclear program.
North Korea's nuclear program was raised with Wang, and separately in three-way-talks between Kerry and his counterparts from Japan and South Korea, during a 10-member Association of Southeast Asian Nations (ASEAN) summit in Brunei.
Kerry said his meeting with Wang showed that Washington and Beijing were cooperating despite tensions over former U.S. intelligence operative Edward Snowden, who was allowed to leave Hong Kong even though Washington made it clear it wanted him returned home to face espionage charges for leaking U.S. government secrets.
"All of us are absolutely united and absolutely firm in our insistence that the future with respect to North Korea must include denuclearization," Kerry told a news conference later.
"China made it clear to me they have made very firm statements and very firm steps they have taken with respect to the implementation of that policy."
Kerry has made clear he wants to see China take a more active stance towards North Korea, which earlier this year threatened nuclear war against the United States and South Korea. Those threats were made during weeks of rhetoric following the imposition of tougher U.N. sanctions in response to Pyongyang's third nuclear test.
He said the issue would be discussed next week in Washington during a security and economic dialogue with Chinese officials.
"In the end we know the only way we will find the stability we want, the peace we want, is for North Korea to honor its commitments made under the September 19, 2005 joint statement on six-party talks which refers very specifically to verifiable denuclearization," Kerry added.
During the talks in the oil-rich sultanate of Brunei, Kerry said there was an agreement to "intensify efforts" to ensure North Korea abandoned its nuclear program.
The United States and its allies believe the North violated the 2005 aid-for-denuclearization deal by conducting a nuclear test in 2006 and pursuing a uranium enrichment program that would give it a second path to a nuclear weapon in addition to its plutonium-based program.
Six-party aid-for-disarmament talks, involving the two Koreas, the United States, Japan, Russia and host China, collapsed in 2008 when the North walked away from the deal.
Beijing is the main economic and diplomatic lifeline for the impoverished and isolated state, whose three nuclear weapons tests since 2006 have threatened Asia's security.
China has boosted sanctions on its ally and has also closed access for North Korean banks.
South Korea's Foreign Minister Yun Byung-se stressed that the North's nuclear program would not be tolerated.
"North Korea will face further isolation and dire consequences in the event of provocations," he said shortly before talks with Kerry began.