South Korea has confirmed its intention to deploy an additional 20 F-35A fighter aircraft by 2028 to further bolster its aerial strike capabilities amid concerns over Pyongyang’s rapid military buildup and growing missile arsenal.

The country’s Defense Acquisition Program Administration (DAPA) said that the Defense Project Promotion Committee has endorsed a "basic" strategy — subject to adjustments following a feasibility study and other procedures — to acquire the multirole stealth fighters from the United States under a 3.9 trillion won ($2.9 billion) program expected to begin in 2023 and be completed five years later.

The project, which DAPA says is in line with South Korea’s “future battlefield operations concept,” will expand the country’s F-35A fleet to 60.

The new aircraft are likely to be from the latest “Block 4” variant, which is expected to feature incremental software upgrades and a longer range, as well as the ability to carry more weapons and allow the crew to operate unmanned aircraft.

DAPA was quoted by the South's Yonhap news agency as saying that the additional F-35As will also help minimize the "defense vacuum" that could emerge as aging fighters are decommissioned.

Stealth fighters such as the F-35 could give Seoul a strategic edge by being able to penetrate North Korea’s air defenses, leaving the country vulnerable to airstrikes against key targets and military facilities. Possessing such a capability has become increasingly important for South Korea, as Pyongyang has threatened to deploy tactical nuclear weapons in the event of a conflict.

The DAPA announcement comes after South Korea’s Defense Ministry revealed in late March that all 40 F-35As ordered for the nation’s air force in 2014 are now in service.

Then-Defense Minister Suh Wok said at the time that the air force plans to use the F-35A “with its all-weather stealth and precision-strike capabilities to achieve overwhelming strategic victories and maintain a full military posture that will deter further North Korean actions.”

South Korea acquired the 40 “Block 3” F-35As under a 7.3 trillion won deal approved in September 2014 that also included related equipment, support and training.

South Korea declared initial operational capability for the Block 3 jets in December 2019. One of the fighters was damaged during an emergency belly landing earlier this year at Seosan Air Force Base.

Meanwhile, the country is also progressing with the development of its own multirole fighter aircraft, with Korea Aerospace Industries aiming to conduct the first flight of the locally developed KF-21 Boramae fighter later this month.

The prototype, the first of six built so far, was seen taxiing on a runway at KAI’s manufacturing facility in early July in Sacheon, about 440 kilometers south of Seoul.

Yonhap has quoted KAI as saying that the six KF-21 prototypes will conduct a combined 2,000 flight tests through 2026. Once aircraft development is complete, South Korea will become one of the few countries operating homegrown supersonic fighter jets. Seoul aims to use the KF-21 to help replace its fleet of F-4E Phantom II and F-5E/F Tiger combat aircraft.

Mass production of the KF-21 is expected to start in 2026 with the “Block 1” aircraft, which will be equipped with limited air-to-ground weapons and air-to-air weapons. From 2028, the “Block 2” aircraft will be capable of performing full air-to-air and air-to-ground combat missions. The South Korean Air Force is planning to acquire 40 of these fighters by 2028 and another 80 by 2032.

Indonesia is the only foreign partner in the approximately 8.1 trillion won development program, with it agreeing to shoulder 20% of the development costs.

The aircraft, which will be equipped with advanced sensors, avionics and weapon systems, will feature three "hardpoints" under each wing for weapons and/or external fuel tanks, and will also be capable of carrying four missiles under the fuselage, according to KAI.

In its 2021-2025 Mid-Term Defense Plan, the South Korean Defense Ministry confirmed that the country would begin developing long-range air-to-surface and air-launched anti-ship guided missiles for integration with the KF-21.

South Korea is also working on other technologies, including advanced air defense systems, precision-strike weapons, reconnaissance satellites and unmanned vehicles, to bolster its defenses against a potential North Korean attack.