Bahrain, Egypt, Saudi Arabia and United Arab Emirates (UAE) say they will close their airspace to Qatari aircraft, after cutting diplomatic ties with the Gulf state which they say is supporting terrorist groups.
Bahrain and UAE say the closure of their airspace will take place "within 24 hours", while Egypt and Saudi Arabia have yet to specify when the closure will take effect.
In a series of tweets, Saudi's foreign affairs ministry says the move is necessary to prevent the country from "the dangers of terrorism and extremism", adding that Qatar has continually supported Yemen's Houthi rebels.
Bahrain and UAE say Qatar's "policy of destabilising the security and stability of the region", prompted them to severe the diplomatic relationship.
Qatar Airways has not made any statement on the likely cancellation of flights to the four countries. A search on the airline's website shows that flights remain available from Doha to Cairo, Jeddah and Riyadh.
FlightGlobal schedules data shows that Qatar Airways flies to Bahrain, along with three destinations in Egypt, nine cities in Saudi Arabia, and four cities in the UAE.