Countries across the region shut their airspace as Iran retaliated against US allies, Qatar saying it had blocked an attack on its airport, one of the major hubs in the region.

At least 12,903 flights were cancelled between Saturday and Monday -- 40 percent of planned departures, according to aviation data analysis firm Cirium, which estimated more than one million passengers had been affected so far.

- Slow resumption -

On Sunday, nearly all flights were cancelled out of the United Arab Emirates, home to Dubai airport, the second-largest in the world in terms of passengers.

The cancellation rate fell to 93.5 percent on Monday after Dubai -- and Abu Dhabi's airport -- resumed limited operations.

Some Emirates flights took off Tuesday morning, according to the Flightradar24 flight tracking website, flying south out of the Gulf region. Low-cost flydubai and Russia's Aeroflot were also said to be operating.

Flights continued to come in and out of Jordan, Saudi Arabia and Oman, though no civilian flights passed through airspace over Iraq, Israel, Kuwait, Libya or Qatar.

Israel said its airspace would gradually reopen from Wednesday night, initially just for flights repatriating nationals.

- Evacuations -

European countries including the Czech Republic, Slovakia and Romania were quick to organise an airlift of their countrymen.

Hundreds of passengers landed back in Prague on two planes on Tuesday morning, with around 100 Slovaks arriving and more than 300 Romanians returning via Egypt.

Italians were set to arrive in Rome and Milan on three flights.

Russia said it had picked up nationals who had fled from Iran to Azerbaijan, as well as a few dozen who were in Egypt.

The United States said it was helping to arrange charter flights from Jordan, Saudi Arabia and the United Arab Emirates -- adding that more than 9,000 people had already made it back from the region since Saturday.

France is among the most affected Western nations, with an estimated 400,000 nationals in the region.

French President Emmanuel Macron said Tuesday two flights were on their way to Paris with the first groups to be repatriated.

Other European countries were following suit.

Germany said a charter flight would leave Oman on Wednesday with some of the estimated 30,000 Germans stranded in the region, and travel firm TUI started to fly home holidaymakers stranded on two of its cruise ships in the Gulf via Dubai.

Britain said a charter flight would bring home nationals from Oman in the coming days, with Ireland and Spain making similar announcements.

Airlines were playing a part too. Three Indian carriers -- IndiGo, Air India Express and Akasa Air -- said they would be running evacuation flights.

British Airways said it had scheduled a flight from Oman on Thursday.

- Suspended operations -

Airlines including Air France, British Airways, LOT, Norwegian and SAS have all suspended flights to the Middle East for the coming days. Finnair has halted flights to Doha and Dubai until nearly the end of the month.

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AEROFLOT - RUSSIAN AIRLINES

TUI AG

Air France-KLM

SAS

FINNAIR