Former U.S. Secretary of State Henry Kissinger is urging the international community to step up efforts to seek North Korea’s cooperation in resolving the nuclear issue in the communist state.

Appearing on a TV program on Tuesday, Kissinger singled out the North’s nuclear issue as a pressing matter that needs to be swiftly resolved.

He said that if Japan, China, Russia and the U.S. fail to denuclearize the North by not exacting enough pressure on such a resource-deprived nation, it would raise questions about the effectiveness of an international system.

As a way to resolve the North’s nuclear standoff, the former state secretary proposed using diplomacy and pressure concurrently.