The world has exhausted all options for dealing with North Korea and the situation cannot be resolved until there's a change in the regime's direction, or a change in the regime, former United States Defense Secretary William Cohen told CNBC Monday.

Kim Jong Un in an undated picture released by the state-run Korean Central News Agency (KCNA) on March 11, 2017. NTS / KCNA / KNSKSN / AFP - Getty Images

"There are no good options that are available right now, we've tried them all. I've been, over the years, involved in the six-party talks in seeing if we could find a way to work together, but it's always one step forward, two back," Cohen said at the sidelines of the China Development Forum in Beijing.

"That would be the most difficult issue to resolve. I think that's the most dangerous issue we have facing us today. Kim Jong Un seems dedicated to being even more provocative, more aggressive," he added.

Geopolitical tensions heightened in recent weeks after North Korea launched ballistic missiles into the Sea of Japan and tested a new type of high-thrust rocket engine. The potential deployment of a U.S. anti-missile system in South Korea saw China retaliating against Seoul.

This story originally appeared on CNBC.

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