North Korea nuclear test site
© Kim Hong-Ji / ReutersA man walks past a TV broadcasting a news report on the upcoming dismantling of the Punggye-ri nuclear testing site, in Seoul, South Korea, May 23, 2018.
North Korea has dismantled its nuclear test site at Punggye-ri, according to RT's Igor Zhdanov, who is part of a journalist pool that witnessed the event.

According to Zhdanov, the journalists were shown three of four tunnels used for nuclear tests at the site. One of them, the northern tunnel, had been used extensively for recent nuclear testing, he said.

The North Koreans explained that the two other tunnels were new and would have likely been used for tests in the near future. Demolishing the tunnels, Zhdanov said, "was a real way of showing how they are ready to make real concessions."

He said the explosions used to destroy the tunnels were "impressive," describing them as "small eruptions of earth and rock." All infrastructure at the site - including barracks and security checkpoints - were destroyed by the blasts, Zhdanov reports.

However, he noted that the buildings had been emptied before being demolished. "We were told that they got rid of the equipment earlier. But of course we have no way of verifying that."

North Korea's nuclear weapons institute said on Thursday that Pyongyang was committed to helping build a nuclear-free world. The institute said that staff from the Punggye-ri test site were being evacuated, and that it was now "impossible" for nuclear tests to be conducted there.

"Finally, being told to pack our bags, meeting in the hotel lobby in an hour. Destination: Punggye-ri nuclear test site," Zhdanov's last tweet reads, posted on Wednesday. He and the other journalists would have to hike for about one hour to reach the remote test site, according to Zhdanov's previous reports.

Pyongyang promised to close the test site in April, announcing the decision after a historic summit between North Korean leader Kim Jong-un and South Korean President Moon Jae-in.

The test site's destruction apparently did not have the intended effect. The White House announced on Thursday that it was cancelling a June summit between Kim and Trump in Singapore "based on the tremendous anger and open hostility" from Kim. The statement claims that Pyonyang had threatened the US with a "nuclear to nuclear showdown."