North Korea said Thursday that it "completely" dismantled its only known nuclear test site, calling the move an important process toward global nuclear disarmament.

In a statement carried by the North's state-run Korean Central News Agency, the North's nuclear research institute said the dismantlement led to the collapse of all the tunnels at the Punggye-ri site and the closure of their entrances. 

South Korean citizens watch dismantling the nuclear test site in Punggye-ri in North Korea on Thursday. (Yonhap)
"The Nuclear Weapons Institute of the DPRK held a ceremony for completely dismantling the northern nuclear test ground of the DPRK on May 24," the institute said, using the abbreviation of the North's official name, the Democratic People's Republic of Korea.

"Dismantling the nuclear test ground was done in such a way as to make all the tunnels of the test ground collapse by explosion and completely close the tunnel entrances, and at the same time, explode some guard facilities and observation posts on the site,"

it added. (Yonhap)