Red Flag military exercise in Nevada, U.S.
A B-52 aircraft from the U.S. Air Force is parked at Nellis base during the annual Red Flag military exercise between the United States, Britain and Australia, in Nevada, February 8, 2023. Reuters

A U.S. B-52 strategic bomber joined military exercises with South Korea on Wednesday in the latest demonstration of the allies' readiness to respond to any North Korean provocation, South Korea's defence ministry said.

The bomber, in the first deployment to South Korea of a U.S. B-52 since March 6, joined U.S. F-35B and F-16 fighters, and South Korean F-35 jets for the exercise, the ministry said.

North Korea has been ramping up its military activity in recent weeks, unveiling new, smaller nuclear warheads, pledging to produce more weapons-grade nuclear material and testing what it called a nuclear-capable underwater attack drone.

The South Korean ministry said the participation of the B-52 would improve U.S. extended deterrence - a reference to the American nuclear umbrella protecting its allies.

"Through combined air exercises linked to the deployment of U.S. strategic assets with increased frequency and intensity, the allies demonstrated their strong will and perfect posture to respond quickly and overwhelmingly to any provocations by North Korea," Park Ha-sik, commander of South Korea's Air Force Operations Command, said in a statement.

U.S. and South Korean forces have been carrying out various training exercises since March, including air and sea drills involving a U.S. aircraft carrier and B-1B bombers, and their first large-scale amphibious landing exercises in five years.

North Korea has reacted angrily to the drills, calling them a rehearsal for war.

South Korean President Yoon Suk Yeol, at a policy meeting with aides, said the regional security situation was "more serious than ever" due to North Korea's weapons development and what he called its ceaseless provocation.

He called for strengthening the alliance's extended deterrence and ensuring the readiness and capabilities of the South Korean military through effective training.