The Joint Chiefs of Staff (JCS) of the South Korean military was quoted as saying by Yonhap news agency that it detected the launch from the Sunan area in Pyongyang at 5:22 p.m.

It did not provide other details immediately.

"While strengthening its monitoring and vigilance, our military is maintaining a full readiness posture in close cooperation with the United States," the JCS said in a text message sent to reporters as quoted by the news agency.

North Korea earlier fired a short-range ballistic missile on Jan. 1.