SEOUL, April 3 -- The Democratic People's Republic of Korea on Friday test-fired four short-range missiles into its western waters, a South Korean Defense Ministry official said.

The official said by phone that the DPRK launched four projectiles, estimated to be short-range missiles, into the western waters from Dongchang-ri in North Pyongan Province between 4:15 p.m. and 5:00 p.m.. The projectiles flied about 140 km.

At about 10:30 a.m. Thursday, the DPRK also fired one short- range projectile, which seems to be the same kind as those launched on Friday, the official said.

The South Korean military believed that those projectiles were short-range KN-02 missiles given their range, pace and trajectory.

The test-firing came in protest against the ongoing joint annual war games between the United States and South Korea and some South Korean civic groups seeking to float anti-DPRK leaflets across the border.

The "Key Resolve" command post exercise ended in March 13, but the "Foal Eagle" field training exercise, which kicked off on March 2, is scheduled to last until April 24.