North Korea fired another two short-range ballistic missiles from an area north of Kaesong, only about 20 km away from the demilitarized zone, into the East Sea on early Sunday morning.
Last Wednesday, the North fired two short-range ballistic missiles from a site in North Hwanghae Province about 40 km from the DMZ.
"Around 1:20 a.m. and 1:30 a.m. on Sunday, the North fired two short-range ballistic missiles into the East Sea," a spokesman for the Joint Chiefs of Staff here said. "We presume that they flew some 500 km."
The missiles are believed to be Scud-C with a range of 500 km or modified Scud-C with an extended range of 700 to 900 km.
It is likely that the North fired the missiles to protest the arrival in Busan on Saturday of the nuclear-powered aircraft carrier USS George Washington belonging to the 7th U.S. Fleet.
The North's National Defense Commission had urged the South to "make a right choice," while calling the USS George Washington's entry into Busan a provocation that throws a wrench into efforts to improve cross-border relations.
South Korean and U.S. military authorities are taking note of the North's intention to fire missiles close to the DMZ rather than from a coastal site. They believe the North Korean regime is trying to ratchet up threats to the South.
Military authorities speculate that the North wants to show it can neutralize South Korea's so-called "kill chain," whereby the military can detect signs of an impending ballistic missile launch and preemptively destroy it.
The North has fired a total of 97 medium and short-range projectiles since Feb. 21, including rockets from new 300 mm multiple rocket launchers, Scud and Rodong missiles, and FROG rockets.