North Korea on Friday fired a short-range ballistic missile (SRBM) into the East Sea and about 170 artillery shots into maritime "buffer zones" set under a 2018 inter-Korean military tension reduction accord, the South Korean military said.

The provocative move came after more than 10 North Korean warplanes staged a menacing flight close to the inter-Korean border, prompting the South Korean Air Force to scramble its F-35A stealth fighters and other assets to the scene, according to the Joint Chiefs of Staff (JCS).

The JCS said it detected the SRBM launch from the Sunan area in Pyongyang at 1:49 a.m., and that the missile flew some 700 kilometers at an apogee of 50 km at a top speed of about Mach 6.

It also detected the North's firing of some 130 artillery shots into the Yellow Sea from Majang-dong, Hwanghae Province, between 1:20 a.m. and 1:25 a.m., and of some 40 artillery shots into the East Sea from Gueup-ri, Gangwon Province, between 2:57 a.m. and 3:07 a.m.

The artillery shots landed in eastern and western buffer zones north of the Northern Limit Line, the de facto inter-Korean sea border, which were delineated under the two Koreas' Comprehensive Military Agreement (CMA) signed in 2018 to reduce tensions. 

The JCS criticized the artillery firing as a "clear" violation of the CMA and the SRBM launch as a breach of UN Security Council resolutions.

"Such continued provocations by North Korea are acts that undermine peace and stability not only on the Korean Peninsula, but also in the international community," the JCS said in a text message sent to reporters.

"Regarding this, we gravely warn (the North) and strongly urge it to immediately stop them," it added.

JCS Chairman Gen. Kim Seung-kyum and Gen. Paul LaCamera, the commander of the South Korea-US Combined Forces Command, had virtual consultations and reaffirmed their commitment to further strengthen the allies' combined defense posture.

On Wednesday, Pyongyang also fired two long-range strategic cruise missiles, involving units operating "tactical nukes," the KCNA has reported.

The North, in addition, announced Monday that leader Kim Jong-un had inspected military drills involving the units in charge of tactical nukes from Sept. 25 to Sunday, during which it staged a series of provocations, including the Oct. 4 launch of an intermediate-range ballistic missile (IRBM).

The drills were organized under "inevitable" circumstances in reference to the deployment of the USS Ronald Reagan aircraft carrier to the East Sea for naval drills with South Korea, according to the KCNA. (Yonhap)