However, officials from the Defense Security Cooperation Agency (DSCA) told Congress in March the fighter sales "will not negatively alter the basic military balance in the region," according to a pair od DOD statements issued Wednesday.
The U.S. warplanes and associated weaponry will provide the South Korean forces "with a credible defense capability to deter aggression in the region, and ensure interoperability with U.S. forces," against potential adversaries in the region, according to the DSCA.
Those fighter jets will replace the current fleet of F-4 Phantoms that make up the majority of the South Korean air force. Seoul is reportedly close to selecting either the F-15, F-35 or the Eurofighter Typhoon for their fleet.
"This proposed sale will contribute to the foreign policy goals and national security objectives of the United States by meeting the legitimate security and defense needs of an ally and partner nation," agency officials added.
News of the sale, first reported by Reuters, comes just as the defense department is ramping up its military presence in the Western Pacific amid threats from North Korean dictator Kim Jong Un.
The escalating crisis with North Korea was prompted by Pyongyang's recent, repeated violations of United Nations sanctions on the country's nuclear and long-range missile tests.
On Wednesday, the Pentagon ordered the deployment of an anti-ballistic missile weapon known as the Terminal High Altitude Area Defense system (THAAD) to positions in Guam.
On Tuesday, Pentagon announced it was deploying the USS Decatur and USS McCain into the Western Pacific, as part of a "missile defense mission" in the region, according to DOD Press Secretary George.
Both Arleigh Burke-class Navy destroyers are equipped with the Aegis missile defense system, which is essentially a sea-based version of the THAAD weapon.
In response, the General Staff of the Korean People's Army claimed Wednesday that it now has final approval to launch a nuclear strike against the United States.
Pyongyang, however, does not yet have the capability to launch a nuclear weapon that can reach U.S. soil, and most experts say the country is still years away from possessing the technology to do so.
Aside from nuclear threats, North Korea has its long-range artillery and rocket units aimed at Seoul on full alert and recently eliminated a military hotline with South Korea. And earlier this month, Pyongyang officially terminated the 1953 armistice with South Korea that ended the Korean War.
--updated at 2:52pm.