US Secretary of State John Kerry on Thursday urged China to play a "positive, constructive" role at the United Nations on a resolution to rein in Syria's chemical weapons.

The top US diplomat acknowledged at the start of talks with Chinese Foreign Minister Wang Yi that the two sides have "disagreed sharply" over the global response to Syria's use of chemical arms.

In the past Beijing --- which like Washington is a veto-wielding permanent member of the UN Security Council -- has blocked resolutions seeking to condemn the regime of Syrian President Bashar al-Assad during the brutal civil war now in its third year.

But Wang said he was ready for "in-depth" talks on all issues, including Syria, "with an open mind."

Beijing has already welcomed a Russian-US framework hammered out in Geneva last week under which Assad would surrender his chemical weapons stockpile to international control.

"While we appreciate China's support for a political solution -- the only solution we believe is ultimately available and possible -- we do have differences between our nations and have disagreed sharply over how the international community should respond to the Syrian regime's use of chemical weapons," Kerry said as the two men began talks at the State Department.

"With negotiations ongoing at the Security Council, we look forward to China playing a positive, constructive, important role," he added.

Wang replied that Beijing believed the framework deal need to be approved by the Organization for the Prohibition of Chemical Weapons.

"At the same time the Security Council of the United Nations also needs to recognize and support this decision," he stressed.

The world's chemical weapons watchdog will meet on Sunday to discuss the Russian-US plan to destroy Syria's arsenal, while at the UN Security Council the five permanent members are hammering out a draft resolution.

"Ultimately, the issue of Syria needs to be resolved through political means. The Chinese side will continue to play its positive and constructive role in that direction," Wang said.

The two ministers were also to discuss the denuclearization of North Korea and ways to relaunch the stalled six-party talks as well as climate change and cybersecurity.

Wang said he was "confident that we will be able to reach new, important agreement" on how to resume the talks aimed at getting Pyongyang to halt its suspect nuclear program.

Kerry said Thursday's talks reflected US commitment to strengthening ties to both Beijing and the Asia-Pacific region and avoiding "falling into a trap of seeing one another as strategic rivals."

"Importantly, part of our new relationship is a commitment to engage in frank discussions on sensitive issues, particularly where we disagree, where misunderstanding could lead to a miscalculation," Kerry stressed.

Speaking through an interpreter, Wang said there was now "strong momentum" in China-US ties and he had come to Washington "to push forward the building of this new model of major-country relationship...with concrete actions and ... our specific cooperation."