Bart Jansen

USA TODAY

The Federal Aviation Administration said Thursday after the crash of Malaysia Airlines flight 17 that U.S. airlines have voluntarily agreed to avoid airspace near the Russian-Ukraine border.

"The FAA is monitoring the situation to determine whether further guidance is necessary," the agency said.

Because of hostilities between Ukraine and Russia, the threat of military action against a civilian airliner has been in the air for months.

FAA prohibited U.S. airlines in April from flying over Crimea, but because of concerns about air-traffic control rather than military action.

The region covered by the FAA order is south of where Malaysia Airlines Flight 17 crashed on Thursday.

"Based on the information currently available it is believed that the airspace that the aircraft was traversing was not subject to restrictions," the International Air Transport Association, which represents airlines worldwide, said in a statement.

But the FAA took the action April 25, which is to remain in effect for one year, because of a dispute between Ukraine and Russia about which country controlled the airspace in the Simferopol region, which covers the Crimean peninsula.

The Russian Federation declared March 28 that it controlled the airspace over Crimea, as well as international airspace above the Black Sea and Sea of Azov. In response, Ukraine created a prohibited area over the Crimean peninsula for flights below 29,000 feet.

Because of the dispute, the International Civil Aviation Organization, a branch of the United Nations, warned airlines April 3 to avoid the area.

"In addition, political and military tension between Ukraine and the Russian Federation remains high, and compliance with air traffic control instructions issued by the authorities of one country could result in a civil aircraft being misidentified as a threat and intercepted or otherwise engaged by air defense forces of the other country," FAA said.