In light of worsening relations between the U.S. and Iran, the FAA has published new guidance on the overflight risk of the Middle Eastern country and the Tehran flight information region (FIR). A Notam published last week warned that all U.S. air carriers and commercial operators should “exercise caution when flying into, out of, within, or over the Tehran FIR.”

As background, the agency noted a wide array of military activities occurring in the area, with heightened Iranian air defense sensitivity. Russian air-launched cruise missiles fired from over Iran at targets in Syria, and Russian sea-launched cruise missiles from the Caspian Sea pose threats to civil aviation, as does Iranian surface-to-surface missile fire from Western Iran, aimed at ISIS positions in the region.

Flight Service Bureau added that operators planning an overflight of the area should weigh the risks of an emergency landing at Tehran or other airports as the U.S. State Department currently advises against travel to Iran due to the risk of arbitrary arrest and detention of U.S. citizens. The U.S. does not have an embassy in the country, and those who are forced to land in Iran should contact the Foreign Interests Section of the Swiss Embassy in Tehran, the State Department said.