North Korea on Thursday fired two unidentified projectiles into the East Sea from an area near its east coast city of Wonsan.

South Korea's Joint Chiefs of Staff(JCS) said that the North "fired one unidentified projectile at 5:34 a.m. and the other at 5:57 a.m., from Wonsan areas into the East Sea, and they flew around 430 kilometers." 

The JCS said South Korean and U.S. intelligence authorities are analyzing what was launched. 

It added that the South Korean military is closely monitoring the situation in case of additional launches while maintaining a readiness posture.

The latest launches came 77 days after the North fired short-range missiles on May 9, which flew 420 kilometers and 270 kilometers, respectively, before landing in the East Sea.