South Korea and the US fired eight ballistic missiles on Monday in response to North Korean missile tests the day before, according to Seoul's military.
The allies launched the ground-to-ground Army Tactical Missile System (ATACMS) at targets in the East Sea, commonly known as the Sea of Japan, according to the Joint Chiefs of Staff.
The 10-minute salvo comes a day after North Korea launched eight short-range ballistic missiles in response to a joint military exercise between South Korea and the United States involving a US aircraft carrier."Our military strongly condemns the North's series of ballistic missile provocations and firmly urges it to immediately cease acts that heighten military tensions on the peninsula."
According to the US Indo-Pacific Command, one US army missile and seven South Korean missiles were shot from the northeast of South Korea during Monday's live-fire practice to demonstrate their capacity to "react promptly to crisis circumstances.
The launches on Monday represent the allies' second such joint show of force under South Korea's hawkish new President, Yoon Suk-yeol, who has promised a harsher approach towards Pyongyang.
"Our government will respond decisively and firmly to any provocations from North Korea," Yoon said during a Memorial Day speech on Monday.
Seoul and Washington conducted coordinated launches last month after Pyongyang launched three ballistic missiles, including a potential intercontinental ballistic missile, in their first such cooperative operation since 2017.
Despite punishing economic penalties, Pyongyang has stepped up its weapons development, with authorities and analysts warning that the government is planning a new nuclear test.
North Korea has conducted a flurry of sanctions-breaking weapons tests this year, including the full-range launch of an intercontinental ballistic missile.