North Korea may test a nuclear weapon on Saturday morning, according to U.S. government sources.

The Daily Caller reports:

The North has reportedly installed a nuclear device inside one of the tunnels at its Punggye-ri Nuclear Test Site, reports Voice of America’s Steve Herman, citing government and other sources. A provocation is expected Saturday, but it could possibly come sooner.

Saturday is the “Day of the Sun,” the 105th anniversary of the birth of North Korean founder. This would be the North’s sixth nuclear test.

“We have no comment at this time, but we will be watching closely,” a National Security Council official told VOA.