Second, a senior administration official said Obama was advised prior to the crash that some commercial airlines, as early as last spring, ceased flying routes over eastern Ukraine, to protect the safety of passengers and crews. Korean Air, Asiana, Qantas and China airlines were among the carriers that chose new routes in the wake of Russia’s annexation of Crimea.

After Flight 17 broke apart, Eurocontrol, the European flight safety organization, said the plane was at 33,000 feet when it disappeared from radar, just 1,000 feet above restricted air space. Ukrainian authorities had previously closed the same flight route from 32,000 feet down to the ground, leaving open the higher flight path.

U.S. intelligence officials who briefed reporters Tuesday at the Office of the Director of National Intelligence refused to answer questions about any warnings or advisories the U.S. government may have shared with peer civil aviation organizations worldwide prior to the Malaysian Airlines incident. The Federal Aviation Administration has not commented.