US Secretary of State John Kerry and Chinese Foreign Minister Wang Yi agreed Thursday on the need for a binding UN Security Council resolution on Syria's chemical arms, a US official said.

Kerry and Wang "were in strong agreement" on the need to act quickly to nail down a UN Security Council resolution, the official said.

But it remained unclear whether Beijing -- a veto-wielding member of the UN Security Council -- would throw its weight behind the language of a resolution currently being drafted.

"On Syria both ministers were in strong agreement on the need for a mandatory and binding UN Security Council resolution," a senior State Department official said.

"They discussed the value of unity among the P5 and both felt it is important for the council to act quickly.

"And for the OPCW to similarly act quickly," the official added, referring to the Organization for the Prohibition of Chemical Weapons, which oversees treaty compliance.

But he refused to be drawn on whether the two men had discussed the issue of how to enforce any resolution over their breakfast meeting at an upscale New York hotel.

"I think that gets us into the molecular structure of the conversation," the US official said, adding it was "a greater level of detail than I can go into."

During Syria's civil war which erupted in March 2011, China and Russia have three times vetoed UN Security Council resolutions seeking to condemn the regime of Syrian President Bashar al-Assad.

And it remained unclear whether Beijing would back the new resolution being drafted by the United States and Russia to bring Syria's chemical weapons stockpile under international control.

"This was not a negotiating session, this was a strategy session," the US official insisted.

Russian and US envoys to the United Nations are currently fine-tuning a resolution on Syria which both sides want to bring to the UN Security Council.

But the two sides appear to have hit a hurdle on what kind of sanctions would be slapped on Syria if it violates the resolution.

Asked whether Beijing would back the resolution, the US official said: "I can't think of anything I heard this morning that would provide an indicator one way or another."