The official closure of Punggye-Ri will come a few weeks before Kim Jong-Un meets US President Donald Trump on June 12 in Singapore.
It was demolished a few buildings operational support.
Last month, North Korea said it would shut its nuclear test site and halt nuclear weapons testing and missile launches ahead of a planned meeting on June 12th between Kim Jong-un and United States president Donald Trump.
The U.S. intelligence community has, with consensus, determined as of mid-2017 that North Korea is capable of mounting compact nuclear weapons atop its larger ballistic missiles, including its intercontinental-range ballistic missiles that threaten the continental United States. He did not specify what the military had seen.
Additionally, some of the rails for the mining carts appear to have been removed, while some carts look like they have been tipped over or disassembled, the monitor said. Or buildings remain intact, including control centre and administrative area, although no vehicles are observed or presence of civilian or military personnel.
Suh said beyond closing tunnels and knocking down buildings, the entire Punggye-ri site will need to be secured to prevent the North Koreans or profiteers from digging up nuclear material that could be reused in weapons or sold on the black market.
"Dismantlement of the nuclear test ground will be done in the following sequence-making all tunnels of the test ground collapse by explosion; completely blocking entries; removing all observation facilities, research institutes and structures of guard units on the ground".
'The implementation of the decision means getting rid of all the nuclear weapons, dismantling them, taking them to Oak Ridge, Tennessee, ' Bolton said in an interview with ABC's This Week.
The Associated Press reports that plans to dismantle the site are not new: During his summit with South Korean President Moon Jae-in in April, Kim announced that he would shut it down by the end of May.
North Korean leader Kim Jong Un announced the decommissioning of the Punggye-ri site during the summit with South Korean President Moon Jae-in in late April, saying that Pyongyang's pursuit for nuclear weapons was complete so the test site was no longer needed.
But days later, the South China Morning Post newspaper reported that the facility had collapsed, threatening an "unprecedented risk" of radioactive fallout.
Pompeo said private-sector Americans could help rebuild North Korea's energy grid and develop the country's infrastructure.
South Korea has said Kim has genuine interest in dealing away his nuclear weapons in return for economic benefits.
The reporters will take photos at the site and cover the dismantlement of the Punggyeri nuclear test site.
The summit will give Trump an early chance "to size Kim Jong Un up and see if the commitment is real", he said.
North Korea blew up a cooling tower at the nuclear facility in 2007 following a deal with the USA, but soon restarted the reactor. They also stated their intention to achieve the denuclearization of the Korean Peninsula.