The U.S. is urging China to exercise its influence on North Korea in order to halt future provocations.

The calls, which follow North Korea’s artillery attack on the South Korean island of Yeonpyeong in the Yellow Sea, were made by both the State Department and the Joint Chiefs of Staff.

In a daily briefing, State Department spokesman Philip Crowley said that China has influence with North Korea and that the U.S. would hope and expect that Beijing will use that influence to reduce tensions that have arisen as a result of North Korean provocations and to encourage the North to take affirmative steps to denuclearize.

He said China is pivotal in moving Pyongyang in a fundamentally different direction.

Admiral Mike Mullen, chairman of the U.S. Joint Chiefs of Staff, said Wednesday that the one country that has influence in Pyongyang is China, so their leadership is absolutely critical.