North Korea fires a new type of the Hwasong-17 intercontinental ballistic missile (ICBM) from Pyongyang International Airport on Nov. 18, in this photo released by the North's official Korean Central News Agency. Yonhap

North Korea fired three short-range ballistic missiles into the East Sea, Saturday, according to South Korea's military, a day after Seoul conducted a test flight of a locally developed solid-propellant space launch vehicle.

The Joint Chiefs of Staff (JCS) said it detected the launches from Chunghwa County, North Hwanghae Province, at 8 a.m., but did not provide any other details.

"While strengthening our 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.

On Friday, South Korea successfully conducted the test of the launch vehicle as part of efforts to strengthen its space-based reconnaissance and surveillance capabilities, according to the defense ministry.

Saturday's missile launch came as Pyongyang is expected to announce its policy goals for 2023 following this week's Central Committee plenary meeting of the ruling Workers' Party.

The saber-rattling added to tensions caused by North Korean drone infiltrations, Monday.

The North fired two short-range ballistic missiles into the East Sea, Dec. 23, less than a week after its launch of two medium-range ones. (Yonhap)