Chinese geologists claim in a new study that the mountain above North Korea’s main nuclear test site collapsed in September, rendering the area unsafe for further testing because of possible radiation leaks — a finding that may shed a different light on Kim Jong Un’s announcement that his country was ceasing its nuclear testing program.

The study carried out by scientists at the University of Science and Technology of China, in Hefei, concluded that the mountain buckled under the stress of multiple explosions caused by the release of huge amounts heat and energy. The study's authors said the area needs close monitoring for leaking radiation.

The data for the study were collected after North Korea's sixth — and most powerful — nuclear test on Sept. 3. It subsequently triggered four earthquakes.

The findings come ahead of Friday’s summit between Kim and South Korean President Moon Jae-in, and also follow Pyongyang's assertion last week that it would halt all missile tests and shut down the nuclear test site, a move interpreted outside North Korea as an attempt by Kim to strike a conciliatory tone.

The study has been peer-reviewed and also accepted for publication by Geophysical Research Letters, a distinguished academic journal published in the United States. A separate study published last month by the same journal found similar results.

On Saturday, President Trump hailed Kim's claim that he would close its nuclear testing facility and suspend nuclear and intercontinental ballistic missile tests as "big progress." North Korea has stopped short of pledging it will entirely give up its nuclear weapons or scale back its production of missiles and their related components.