United Nations Secretary-General Antonio Guterres delivers a speech on disarmament and denuclearisation at the University of Geneva (UNIGE) in Geneva, Switzerland, May 24, 2018. REUTERS/Denis Balibouse

WASHINGTON (Reuters) - U.N. Secretary-General António Guterres said it was unfortunate that no international experts were on hand when North Korea blew up tunnels at its nuclear test site on Thursday even as he welcomed Pyongyang’s reported action.

“It is regrettable that international experts were not invited to witness the site closing,” a spokesman for Guterres said in a statement.