U.S. National Security Adviser Jake Sullivan has cited North Korea as one of the key global issues that require the U.S. and China’s bilateral cooperation.

Sullivan made the remark on Tuesday when he appeared at a virtual seminar hosted by U.S. think tank The Brookings Institution. He spoke on the outcome of a virtual summit between U.S. President Joe Biden and Chinese President Xi Jinping held on Monday. 

Saying the U.S. has seen the North carry out a series of tests, Sullivan said Washington has indicated that it’s ready to engage in “good faith and diplomacy” if Pyongyang is prepared to do the same. 

He went on to stress that coordination around that issue is very important.

The remarks on North Korea were made after he said U.S. engagement with China will intensify at multiple levels to make sure there are "guardrails" so competition between the U.S. and China will not veer off into conflict.

Sullivan said that other than the North Korea issue, Biden and Xi also noted climate change, public health, Iran’s nuclear issue and Afghanistan as other areas where they could work together.