The U.S. Strategic Command said it detected North Korea's launch of two Rodong intermediate-range ballistic missiles and one of them exploded right after launch.

"U.S. Strategic Command systems detected what we assess were two North Korean missile launches," the command said in a statement. "The simultaneous launch of two presumed (Rodong) intermediate range ballistic missiles occurred near the western city of Hwangju."

Initial indications showed that one of the missiles "exploded immediately after launch, while the second was tracked over North Korea and into the Sea of Japan," the statement said, adding that the North American Aerospace Defense Command determined the missile launches from North Korea did not pose a threat to North America.

"The men and women of USSTRATCOM, NORAD and U.S. Northern Command, and U.S. Pacific Command remain vigilant in the face of North Korean provocations and are fully committed to working closely with our Republic of Korea and Japanese allies to maintain security," the statement said.

South Korea and Japan had earlier said the North launched one Rodong missile that flew about 1,000 kilometers and landed in Japan's exclusive economic zone waters. (Yonhap)