"N.Korea May Be Preparing New Nuclear Tests to Improve Arsenal, U.S. and Allies Say" by Josh Smith for Reuters

Reuters reporting recently cited ONN's Developments at the DPRK's Punggye-ri Nuclear Test Site since December 2021.

"There are increasing signs that North Korea could soon test a nuclear weapon for the first time since 2017 in a bid to improve its arsenal and increase political pressure, U.S. and South Korean officials and analysts said.

...

Since December, satellite imagery has showed activity at the main administrative area, the Vienna-based Open Nuclear Network (ONN) said in a report this week.

Notably, the South Portal tunnel that North Korea appears be reactivating was not previously used for testing, the ONN report said. Piles of what might be logs, often used to shore up such tunnels, have also been spotted, it added."