North Korea says it has conducted its first-ever nuclear test.

The North’s state-run Korean Central News Agency reported Monday that the underground test was successful without any radioactive leakage from the site.

Presidential office spokesman Yoon Tae-young said the Korea Institute of Geoscience and Mineral Resources detected a seismic tremor of about three-point-five-seven magnitude following Pyongyang’s announcement.

Yoon went on to say that President Roh Moo-hyun called a meeting of top security-related advisers to discuss the matter.

Upon confirming the nuclear test, the issue will be turned over to a full meeting of the National Security Council.

Yoon added the government was exchanging information with other countries and discussing follow-up measures to Pyongyang’s announced nuclear test.