The United States will take its own measures to deal with the North Korean threat if China is unable or unwilling to help, Secretary of State Rex Tillerson said Friday.

"We would be happy to work with them," Tillerson said after US President Donald Trump hosted his Chinese counterpart Xi Jinping at the pair's first summit.

"But we understand it creates unique problems for them and challenges and that we would and are prepared to chart our own course if this is something China is just unable to coordinate with us."