South moves to bolster air-to-air missile stockpile as North threats grow

South Korea is moving to bolster its wartime interceptor stockpile with additional U.S.-made short-range air-to-air missiles as North Korea expands its cruise missile and suicide drone capabilities. But questions remain over whether the planned purchases are sufficient for a large-scale conflict.

The U.S. State Department provisionally approved on Friday a Foreign Military Sale of 103 AIM-9X Sidewinder Block II tactical missiles and 10 tactical guidance units to South Korea.

The estimated total cost is $125 million, and U.S. defense contractor RTX will serve as the principal contractor.

The deal will be finalized following U.S. congressional review and negotiations between the two countries.

The approval came just over two months after the State Department tentatively approved on June 10 the sale of 70 AIM-120C-8 Amraam medium-range air-to-air missiles and two guidance sections to South Korea. That package was estimated at $292 million.

The timing of the planned acquisition comes as North Korea’s aerial threats grow.

North Korean leader Kim Jong-un ordered in June that the country’s ballistic and cruise missile production capacity be expanded to 2.5 times its existing level within five years. Earlier in November 2024, he ordered the full-scale mass production of suicide drones. 

North Korea unveiled what it described as an AI-guided tactical cruise missile in May and said that it would deploy the weapon to frontline units. In a scenario involving simultaneous incursions by suicide drones and low-flying cruise missiles, the number of interceptors immediately available could become as important as their interception capabilities.

The U.S. military has already increased the number of air-to-air missiles carried by its aircraft in combat to boost the number of targets that they can engage.

One example came in the Red Sea in 2024, when the U.S. Navy urgently adopted a configuration allowing F/A-18E/F Super Hornets to carry as many as nine air-to-air missiles — four AIM-9Xs and five AIM-120s — in response to mass drone attacks by Houthi militia.

The South Korean Air Force, which operates the AIM-9X on F-15K, KF-16 and F-35A fighter jets, also fired the missile against cruise missile and unmanned attack aircraft targets during live-fire exercises in May.

The growing importance of interceptor stockpiles in recent wars may also be a factor behind South Korea’s latest acquisition push. Tactics involving simultaneous launches of relatively inexpensive suicide drones and low-flying cruise missiles to deplete air defense interceptors have repeatedly been seen in the wars in Ukraine and Iran.

Within just three days of the outbreak of the war in Iran, 800 Patriot missiles were used, Ukraine’s defense ministry said in March. The ministry also noted that Ukraine received 600 Patriot missiles during four years of full-scale war.

The Center for Strategic and International Studies, a U.S. think tank, estimated last month that U.S. stocks of Patriot interceptors and Terminal High Altitude Area Defense (Thaad) interceptors had fallen to around 35 to 40 percent of their prewar levels following the Middle East conflict.

The United States signed a seven-year agreement with RTX in February to increase annual Amraam production to as many as 1,900 missiles. On Aug. 3, Washington also announced framework agreements to expand production capacity for Patriot PAC-3 interceptors threefold and Thaad interceptors fourfold.

The moves reflect growing recognition that production capacity and stockpile levels can determine how long military operations can be sustained.

Other countries are also stepping up efforts to stockpile air-to-air missiles.

Last year, the U.S. government provisionally approved AIM-9X-series sales of 300 units to Norway, 340 to Denmark and up to 578 to Belgium.

For the AIM-120 family, Japan requested up to 1,200 missiles last year, and Saudi Arabia sought 1,000. Both potential sales received U.S. State Department approval.

Compared to such moves by other countries, some observers question whether South Korea is acquiring air-to-air missiles quickly enough and in sufficient quantities.

“In a mass aerial attack, 100 AIM-9X Block II missiles could be used up within hours,” a defense industry source said. “Missiles cannot be stored indefinitely, so South Korea needs to continuously acquire new missiles in sufficient numbers to meet wartime operational requirements while replacing aging stocks on time.”

BY LEE KEUN-PYUNG [[email protected]]