One or more unidentified aircraft appear to have approached the inter-Korean maritime border from the North Korean side on Monday, prompting repeated warnings.

The activity by the apparent North Korean aircraft came on the same day as U.S. and ROK forces kicked off annual joint military drills, which Pyongyang has condemned as a “direct military provocation.”

In a message broadcast late Monday morning, a speaker who identifies themselves as a member of the Sixth Marine Brigade’s air defense operations control center warns aircraft approaching the inter-Korean maritime border to immediately move north, according to a marine radio transmission analyzed by