There were no related reports by the secretive nation's media, including the Korean Central News Agency and the Rodong Sinmun, as of 9:30 a.m., unlike Pyongyang's usual practice of quickly boasting publicly about its major weapons tests.

On Wednesday, the North launched a ballistic missile, which flew 470 kilometers at a maximum altitude of 780 km before falling into the East Sea, according to South Korea's military. Some informed sources said it seems to be an intercontinental ballistic missile (ICBM) fired at a lofted angle.

The North's media has usually carried reports, coupled with a number of photos, of such major missile tests the next morning, except for failed launches like the one in mid-March.

Observers here raised the possibility that the North failed to achieve its goal in the latest missile firing, the 14th of this year.

South Korea's national security officials and media are continuing to monitor the North's media for relevant reports that may be issued later Thursday or Friday morning. (Yonhap)