The Federal Aviation Administration urged US-registered planes Thursday to avoid flying over eastern Ukraine, following the apparent shooting down of a Malaysian airliner over the rebel-held region.
The FAA issued the notice "due to recent events and the potential for continued hazardous activities," with restricted areas including the entire Simferopol and Dnepropetrovsk flight information regions.
The so-called Notice to Airman, or NOTAM, "prohibiting US flight operations until further notice" over the area, follows an April FAA ban on flights over the Crimean Peninsula annexed by Russia and adjacent zones of the Black Sea and Sea of Azov.
"No scheduled US airlines are currently flying routes through this airspace," the FAA noted, adding that it would re-evaluate the notice by October 31.
US officials said the Malaysia Airlines jet, which was carrying 298 people, was hit by a surface-to-air missile but could not say who launched the attack and from where.
The flight took off from Schiphol airport in Amsterdam shortly after noon Thursday and was supposed to land in Kuala Lumpur at around 6:10 am Friday local time.