Chairman of the U.S. Joint Chiefs of Staff Admiral Mike Mullen says he believes North Korea will likely engage in further provocations.

During a briefing on U.S. defense strategies in Washington on Monday, Mullen said he believes the North’s communist regime will “once again attempt to provoke hostilities."

He added that South Korean leaders will face some difficult decisions about if and how to respond.

Mullen also said that South Korea has shown great restraint toward the North’s provocations and it would be a dire mistake if the North regards the South’s restraint as a lack of capability or determination to retaliate.