MELBOURNE, Australia — Singapore will exercise a contractual option to acquire eight more F-35B fighter jets, bringing it fleet to 12 aircraft that manufacturer Lockheed Martin will deliver by the end of the decade.

Speaking to lawmakers during a budget hearing, Singaporean Defence Minister Ng Eng Hen said the decision came after a “full evaluation” of the F-35, which followed increased access to the aircraft program thanks to the country’s initial order.

That access included Republic of Singapore Air Force pilots getting the opportunity to fly F-35 mission simulators under the tutelage of operational F-35 instructor pilots, as well as conducting an evaluation of the electronic systems onboard the aircraft.

Singaporean personnel also visited overseas operators to study various aspects of F-35 sustainment, and they flew with Australia and the U.S. Marine Corps operators during a multinational air combat exercise in northern Australia.

The U.S. State Department in January 2020 approved Singapore’s request to buy four F-35Bs — the short-takeoff-and-vertical-landing variant of the Joint Strike Fight. The approval also included an option for eight more aircraft.

The small Southeast Asian island nation has likely selected the F-35B because it can take off fully loaded with a runway of about 600 feet, and land vertically. This allows the Republic of Singapore Air Force to reduce its reliance on long runways and to mitigate potentially devastating effects of an attack on its airfields.

Singapore currently has five established airports and air bases on its 280-square-mile main island, with a smaller emergency landing strip on one of its smaller offshore islands. One of the established bases is due to close in the early part of the next decade.

The Air Force will replace its current fleet of 60 Lockheed Martin-made F-16 Fighting Falcon multirole fighters with the F-35B, with the service to retire the F-16 fleet starting in the early 2030s, according to Ng.

The F-16s are spread among three locally based squadrons and a training detachment based at Luke Air Force Base in Arizona. The detachment is due to move to Ebbing Air National Guard Base at Fort Smith, Arkansas, and will become the Republic of Singapore Air Force’s F-35 training detachment when deliveries begin in 2026.

Accompanying documents released by the ministry during the budget debate also revealed Singapore will acquire ST Engineering’s improved Bronco 3 armored tracked carrier to replace the original Broncos in service with Singapore’s Army. However, the documents did not reveal an acquisition timeline, a quantity of vehicles or a contract value.

The country is setting aside $13.4 billion for its 2023 defense budget, a 5.6% increase over last year’s figure.