N. Korea Launches Ballistic Missile Into Sea: Yonhap

North Korea on Friday test fired a short-range ballistic missile and flew nearly a dozen fighter jets close to the border with the South, Yonhap news agency reported - the latest in a series of military provocations that have sent tensions soaring on the Korean peninsula.

Leader Kim Jong Un has overseen a blitz of ballistic missile launches in recent weeks, which Pyongyang has described as tactical nuclear drills that simulated taking out airports and military facilities across South Korea.

On Friday, the North's military said its latest actions came in response to a "provocative" South Korean artillery exercise near the border.

The Korean People's Army "took strong military countermeasures," said the statement carried by the Korean Central News Agency.

The KPA "sends a stern warning to the South Korean military inciting military tension in the frontline area with reckless action," said the statement.

South Korea's Joint Chiefs of Staff (JCS) said it detected the missile launch from the Sunan area in Pyongyang at 1:49 am, according to Yonhap. It did not provide other details.

Earlier, the JCS said 10 fighters had been detected flying 25 kilometres (15 miles) north of the inter-Korean border late Thursday into early Friday, crossing a Seoul-set "reconnaissance line" that triggers an automatic operational response.

Seoul scrambled military aircraft, including F-35A fighter jets, according to the JCS, Yonhap reported.

Pyongyang test-fired a pair of long-range strategic cruise missiles on Wednesday, according to state media -- tests personally supervised by Kim.

The cruise missiles -- which travel at lower altitudes than ballistic missiles, making them harder to detect and intercept -- flew 2,000 kilometres (1,240 miles) over the sea before hitting their targets, KCNA said.

Kim expressed "great satisfaction" with the recent tests, which he said showed the country's nuclear combat forces were at "full preparedness for actual war" and sent a "clear warning to the enemies," KCNA said.

With talks long stalled, and Ukraine-linked gridlock at the United Nations stymying the chance of fresh sanctions, Kim has doubled down on developing and testing his banned nuclear arsenal.

Officials in Seoul and Washington have been warning for months that Pyongyang is ready to conduct another nuclear test -- which would be the country's seventh.

Kim said North Korea will "focus all efforts on the endless and accelerating development of the national nuclear combat armed forces," KCNA reported Thursday.

He made acquiring tactical nukes -- smaller, lighter weapons designed for battlefield use -- a top priority at a key party congress in January 2021.

Pyongyang is not technically banned by the UN from testing cruise missiles, but all ballistic missile launches violate sanctions and are typically flagged by Seoul or Tokyo. Neither had alerted the Wednesday test.