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