Iran has issued a NOTAM warning that unmanned aerial vehicles (UAVs) will operate from ground level up to 10,000 feet (around 3,300 meters) near its border with Azerbaijan.

The platform also published the coordinates of the maritime area in the Caspian Sea where the notice applies, The Caspian Post reports via flight monitoring service Flightradar24.

A NOTAM (Notice to Air Missions) is an official alert distributed via telecommunication channels to inform flight crews about changes to airspace conditions, navigation systems, regulations, or potential hazards that could affect aviation safety.

In this case, the Iranian notice effectively closes the airspace over a large maritime zone along Azerbaijan’s Caspian border to all types of flights. The move indicates that Iran is conducting drone exercises in the specified area.

The drills over the Caspian Sea come amid heightened regional tensions, including a significant buildup of US military forces in the region and warnings to Tehran of possible military action.