U.S. and South Korean troops commenced a major exercise on Monday with the goal of enhancing their joint defense capabilities against North Korea, which has once again accused both countries of preparing for an invasion. This annual summertime drill comes at a time of increased tensions on the Korean Peninsula, with North Korea conducting frequent weapons tests and the U.S. and South Korea escalating their military exercises in response.

The exercise, known as Ulchi Freedom Shield, will consist of computer-simulated war games and over 40 types of field exercises, including live-fire drills. Both countries have characterized these drills as defensive in nature, aiming to address evolving threats from North Korea such as missiles, GPS jamming, and cyberattacks, while incorporating lessons learned from recent conflicts.

Approximately 19,000 South Korean military personnel will take part in the 11-day drills, which are set to last until August 29. The U.S. has not disclosed the number of American troops involved or whether there will be the participation of U.S. strategic assets. The United States has increased the deployment of bombers, submarines, and aircraft carrier strike groups in the region for joint training with South Korean and Japanese forces.

North Korea remains defiant, with leader Kim Jong Un overseeing the delivery of nuclear-capable missile launchers to frontline military units and advocating for the continuous expansion of the country’s nuclear program. Analysts suggest that Kim’s actions may be an attempt to pressure the U.S. during an election year, aiming to assert North Korea as a nuclear power and negotiate on favorable terms.

In the past year’s Ulchi Freedom Shield exercises, North Korea conducted ballistic missile tests simulating nuclear strikes on South Korean targets. Recently, the country has engaged in a psychological warfare campaign by sending thousands of balloons carrying trash towards South Korea, further straining relations between the two nations.