Despite the cancelled summit with the U.S., North Korean leader Kim Jong-un went ahead and demolished his country's nuclear test site by blowing up access tunnels on Thursday.
The explosions, that were witnessed by invited international media, were supposed to build confidence ahead of the planned meeting next month between Kim and President Donald Trump.
The blasts were centred on three tunnels at the underground site and a number of buildings in the surrounding area.
North Korea held a closing ceremony afterward with officials from its nuclear arms programme in attendance.
"There was neither leakage of radioactive materials nor any adverse impact on the surrounding ecological environment," said an unnamed official, purportedly the deputy director of the Nuclear Weapons Institute of North Korea.
North Korea's state media called the closure of the site part of a process to build "a nuclear-free, peaceful world" and "global nuclear disarmament". Pyongyang also said it remains open to resolving issues with Washington at "any time, in any way."