The navies of South Korea, the U.S. and Japan conducted maritime missile defense drills in ROK waters on Tuesday, in response to North Korea’s attempted satellite launch last week and its advancement of nuclear and missile capabilities.

Destroyers from the three countries equipped with the Aegis combat system — the ROKS Yulgok Yi I, USS Benfold and JS Haguro — participated in the exercise off the coast of Jeju Island, the ROK navy said in a press release. The participants simulated response procedures for detecting, tracking and sharing information about virtual North Korean ballistic missiles, the navy added.