South Korea's defense authorities approved a 3.94 trillion-won ($2.97 billion) plan Friday to deploy some 20 additional F-35A radar-evading fighters by 2028 as part of efforts to counter North Korea's nuclear and missile threats, according to the state arms procurement agency.

The Defense Project Promotion Committee endorsed the "basic" procurement plan, which is subject to adjustments following a feasibility study and other procedures, according to the Defense Acquisition Program Administration.

The plan came after South Korea completed the deployment of 40 F-35As in January under the country's first project to procure the stealth fighter manufactured by the US defense giant Lockheed Martin.

DAPA said it expects the project to minimize the "defense vacuum" that could emerge as aging fighters are decommissioned. The agency also said a "core asset" to the Kill Chain program will be added to deter possible nuclear and ballistic missile threats from North Korea.

Kill Chain refers to the country's preemptive strike program to be mobilized in a contingency.

The committee also approved a 1.4 trillion-won project to deploy 18 CH-47F Chinook helicopters manufactured by the US firm Boeing by 2028. The project is designed to replace the aging fleet of CH-47D helicopters. (Yonhap)