North Korea staged its second short-range missile test in four days early Sunday, Korean time, South Korean officials reported.

The Yonhap News Agency said North Korea did not issue any warnings to planes or ships in the area before firing two missiles. Both landed in international waters. Pyongyang conducted a similar test Thursday.

"North Korea fired each one missile presumed to be Scuds from the vicinity of Wonsan at about 4:50 a.m. and 4:58 a.m. into the East Sea," the South Korean joint chiefs of staff said. "Their range is about 500 kilometers," it said. Wonsan is on the east coast of North Korea.

The missile tests have come in advance of a scheduled July 3-4 visit to South Korea by Chinese President Xi Jinping.

North Korea claimed Friday it was testing newly developed precision-guided missiles, the Associated Press reported. Agence France-Press said the missile may have been a variant of the Russian KH-35. However, a U.S. defense official told CNN there's "no indication of new North Korean technology."

The Korean Peninsula technically still is at war. Hostilities ended in 1953 with an armistice, not a peace treaty.