The US wants to “pre-negotiate” with China a tough new United Nations sanctions regime against North Korea before Pyongyang conducts another missile or nuclear weapons test, a senior US state department official said on Friday.

The talks will be a key test of US president Donald Trump’s assertion in April that he and his Chinese counterpart, Xi Jinping, would build a “very, very great relationship” between their two countries. 

“We’re discussing with them a new UN Security Council resolution that would be pre-negotiated so we wouldn’t have to undergo this very lengthy delay between the time that something happens and the time we can actually draw up a [resolution],” Susan Thornton, acting assistant secretary for east Asian and Pacific affairs, told reporters in Beijing.