North Korea appears to have blown up tunnels at its only nuclear test site, in a move to reduce regional tensions.
Foreign journalists at the Punggye-ri nuclear testing site in the north-east said they witnessed a huge explosion.
Pyongyang offered to scrap the site earlier this year as part of a diplomatic rapprochement with South Korea and the US.
But scientists believe it partially collapsed after the last test in September 2017, rendering it unusable.
Independent inspectors were not allowed to witness the process of the dismantling of the Punggye-ri site in the mountainous region of the country, and some worry it could be easily reversible, the BBC’s Laura Bicker reports.
This comes ahead of a planned summit between US President Donald Trump and North Korean leader Kim Jong-un in Singapore on 12 June.
However, in recent days both countries have said the meeting could be delayed or even called off.