MOSCOW, April 20. /TASS/. Russia has declared a flight hazard zone for civilian flights in the area over the Black Sea and Crimea, NOTAMs (Notices to Airmen) issued by Russia inform.

Russia has issued three NOTAMs in total. They will be active until April 24 with minor differences. A number of air routes in the Simferopol flight information region over the Black Sea will be fully closed. The flight zone over the Crimean Peninsula remains open.

According to the NOTAMs, in some areas, air routes are suspended only at the height of over 11,900 meters (higher than civilian flights ascend) in some areas, while some zones have introduced restrictions for flights over 6,100 meters. Meanwhile, in certain areas, the shutdown is from sea level.

Earlier on Tuesday, the press service of the Black Sea Fleet informed that within the control inspection of the fleet’s forces for the winter training period, drills involving over 20 ships and boats of the Black Sea Fleet and three squadrons of attack aircrafts of the Southern Military District’s air forces and air defense forces were held.

Earlier, the US Federal Aviation Administration (FAA) issued a NOTAM recommending American airlines to conduct flights over some areas of Russia and Ukraine, namely the flight information regions of Kiev, Dnipro and Simferopol, as well as the Moscow and Rostov-on-Don flight information regions located within 100 nautical miles of them with "extreme caution."