The South Korean military says North Korea fired two ballistic missiles on Monday morning.

In a message sent to reporters, the Joint Chiefs of Staff(JCS) said the military detected two ballistic missiles fired from the Jangyon area in South Hwanghae Province at 5:05 a.m. and 5:15 a.m., traveling in a northeastern direction.

The JCS said the first missile flew about 600 kilometers and the second traveled 120 kilometers. 

It said the military detected, tracked and monitored the missiles immediately after the launch and shared related information with the U.S. and Japan, adding that analysis of the launch is underway. 

The JCS said the military has strengthened its monitoring and vigilance against additional launches and is maintaining a full readiness posture. 

The launch comes five days after the North launched a ballistic missile from the Pyongyang area toward the East Sea last Wednesday, which South Korean authorities said exploded mid-flight.

The following day, the North claimed to have successfully conducted a multiple warhead missile test, but the JCS dismissed the claim as an “exaggeration” to cover up the failed launch.