The South Korean and U.S. militaries launched their biggest joint military exercises in years Monday, as North Korea said it conducted submarine-launched cruise missile tests in apparent protest of the drills it views as an invasion rehearsal.

North Korea’s missile tests Sunday signal the country likely will conduct provocative weapons testing activities during the U.S.-South Korean drills that are to run for 11 days. Last week, North Korean leader Kim Jong Un ordered his troops to be ready to repel its rivals’ “frantic war preparation moves.”

The South Korean-U.S. drills include a computer simulation called the Freedom Shield 23 and several combined field training exercises, collectively known as the Warrior Shield FTX.

South Korean and U.S. authorities didn’t immediately disclose details of Monday’s drills.

But they said earlier the computer simulation is designed to strengthen the allies’ defense and response capabilities amid North Korea’s increasing nuclear threats and other changing security environments. They said the field exercises would also return to the scale of their earlier largest field training called Foal Eagle that was last held in 2018.

A recent U.S. military statement said the field exercises are to further enhance the two militaries’ “cooperation through air, land, sea, space, cyber and special operations, and improve upon tactics, techniques and procedures.”

North Korea said in state media that its launches of two cruise missiles from a submarine off its east coast showed its resolve to respond with “overwhelming powerful” force to the intensifying military maneuvers by the “the U.S. imperialists and the South Korean puppet forces.”

The North’s official Korean Central News Agency on Monday called the missiles “strategic” weapons and said their launches verified the operation posture of the country’s “nuclear war deterrence.” This implies that North Korea aims to arm the cruise missiles with nuclear warheads.

It said the missiles flew for more than two hours, drawing figure-eight-shaped patterns and hit targets 1,500 kilometers (930 miles) away. The missiles were fired from the 8.24 Yongung ship, KCNA said, referencing a submarine that North Korea used to conduct its first submarine-launched ballistic missile test in 2016.

The reported launch details show Japan, including U.S. military bases in Okinawa, is within striking distance of the cruise missiles, if they are fired from the North’s eastern waters, said Kim Dong-yub, a professor at the University of North Korean Studies in Seoul. He added the weapons could reach even the U.S. Pacific territory of Guam if the submarine could operate at a greater distance from North Korean waters.

Sunday’s actions were the North’s first underwater missile launches since it test-fired a weapon from a silo under an inland reservoir last October. Last May, the country test-launched a short-range ballistic missile from the same submarine.

North Korea’s command of submarine-launched missile systems would make it harder for adversaries to detect launches in advance and would provide the North with retaliatory attack capability. Experts say it would take years, extensive resources and major technological improvements for the heavily sanctioned nation to build a fleet of several submarines that could travel quietly in seas and reliably execute strikes.

Kim Dong-yub, the professor, said Sunday’s tests were the North’s first known launches of cruise missiles from a submarine as its previous underwater launches all involved ballistic missiles. He said that North Korea is pushing to obtain various types of missiles and launch platforms to boost its ability to evade detection before launch or interception during flight.

South Korea’s military confirmed the latest North Korean missile launches, saying they were fired from a submarine in waters near the North’s eastern port city of Sinpo on Sunday. Sinpo has a major submarine-building shipyard.

South Korea’s Joint Chiefs of Staff said that it maintains a readiness in close coordination with the United States. It said the South Korean and U.S. intelligence authorities were analyzing details of Sunday’s launches.

After a record number of missile tests last year, North Korea has carried out several additional rounds since Jan. 1. Before Sunday’s launches, the country also test-fired an intercontinental ballistic missile potentially capable of reaching the mainland U.S.; short-range, nuclear-capable missiles designed to hit South Korea; and other weapons.

Experts say Kim, who sees his nuclear arsenal as his best security guarantee, is trying to pressure the United States into accepting the North as a legitimate nuclear power and relax international economic sanctions.

North Korea sees regular South Korea-U.S. military exercises as a major security threat, though the allies say their drills are defensive. Some observers say North Korea uses its rivals’ drills as a pretext to test weapons and modernize its nuclear arsenal to secure an upper hand in dealings with the United States.

In past years, the U.S. and South Korea cancelled or scaled back some drills to pursue diplomatic efforts to denuclearize North Korea and out of concern about the COVID-19 pandemic. The two countries once more expanded exercises after North Korea conducted more than 70 missile tests in 2022 and adopted an increasingly aggressive nuclear doctrine.

In recent weeks, the U.S. flew powerful, long-range bombers for joint aerial drills with South Korean fighter jets. South Korea’s Defense Ministry said the deployment demonstrated U.S. commitment to use a full range of military capabilities, including nuclear, to defend its Asian ally in the event of outright conflict with North Korea.

Last Thursday, Kim supervised a live-fire artillery drill simulating attacks on a South Korean airfield. He ordered his military to maintain the capability to “overwhelmingly respond ” to enemy actions, which he said included “all sorts of more frantic war preparation moves” according to KCNA.

The news agency reported Sunday that Kim also convened a key meeting on military affairs to adopt unspecified steps to make “more effective, powerful and offensive use of the war deterrent” in light of U.S. and South Korean maneuvers.

(AP)