A South Korea defense ministry official told CNN that two of the projectiles failed to launch successfully.
The other two projectiles flew distances of 130 miles and 80 miles, respectively. The one that flew the farthest landed in the sea. It's unclear where the second projectile landed.
All were launched from central North Korea.
In early July, North Korea re-asserted its sovereign right to conduct missile launches. The state-run Rodong Sinmun newspaper wrote on July 6: "It is the inviolable legitimate exercise of the sovereignty that the DPRK has bolstered up its deterrence force for self-defense to defend the security and peace of the country and firmly safeguard the gains of the revolution."