The head of the U.N. is welcoming an announcement by North Korea to close its nuclear test site and says he's also looking forward to the U.S.-North Korean summit.

U.N. Secretary-General Antonio Guterres told reporters Monday in Vienna that "the irreversible closure of the site will be an important confidence-building measure that will configure to further efforts towards sustainable peace and verifiable de-nuclearization of the Korean Peninsula."

North Korea said Saturday it will dismantle its nuclear test site in less than two weeks, a dramatic event prior to leader Kim Jong Un's summit with U.S. President Donald Trump next month. Trump welcomed the "gracious gesture."

Guterres says he is looking forward to "this positive momentum being consolidated at the summit between the leaders of the United States and North Korea."