The International Crisis Group has stressed diplomacy as the best means to deal with North Korea and its nuclear issue.

In a special report on Pyongyang’s nuclear standoff, the Brussels-based nonprofit group said that while diplomacy needs to be backed up by the most effective possible deterrence and containment, it is still the best option.

The group said that while still preserving the six-nation nuclear talks, the U.S. needs to talk to Pyongyang directly at the highest levels and establish liaison offices in the North to remove the North’s deep insecurity about the U.S.

The group then urged the North to return to the six-way nuclear negotiations and called on South Korea to maintain the separation of humanitarian assistance and denuclearization in inter-Korean relations.

China was also called on to consider suspending the “Treaty on Friendship, Cooperation and Mutual Assistance between China and North Korea” until Pyongyang returns to the nuclear discussions.