SEOUL — North Korea has launched an unidentified short-range missile, a South Korean military official confirmed to NBC News.

The missile launched shortly after 9 a.m. Saturday off the eastern area on the Hodo Bando peninsula. South Korean and U.S. authorities are analyzing the details concerning the missile launch, according to the military official.

National Security Advisor John Bolton has "fully briefed" President Donald Trump on the launch, a state department, a senior administration official told NBC News Friday night.

Trump and North Korean dictator Kim Jong Un were unable to negotiate a denuclearization deal during a summit in Vietnam in February.

The president indicated at the time that the discussions stalled over Kim's demand that all sanctions be lifted in exchange for concessions on Pyongyang's nuclear weapons program.

Researchers at Beyond Parallel, a project sponsored by the defense think tank Center for Strategic and International Studies, found in March thatNorth Korea was pursuing the "rapid rebuilding" of the long-range rocket site at Sohae Launch Facility.

Beyond Parallel reported that the activity at Sohae, photographed on March 2, is "evident at the vertical engine test stand and the launch pad's rail-mounted rocket transfer structure."

"The activity they are undertaking now is consistent with preparations for a test, though the imagery thus far does not show a missile being moved to the launch pad," Victor Cha, one of the authors of the report, said.