A volcanic ash cloud from Iceland forced the shutdown on Tuesday of airports for the first time in north Africa and in the Canaries and southern Spain, as it drifted as far as Turkish airspace.
While most European air travel was "close to normal" on Tuesday, the continent's air traffic agency Eurocontrol said, restrictions and airport closings caused flight cancellations as winds pushed volcanic ash in the atmosphere into some new territory.
Eight airports on Morocco's north and west coasts, including Rabat and Casablanca, were shut down, the first time the cloud of ash that has caused air traffic chaos in Europe over the past month has affected north Africa's airspace.
Casablanca -- the hub of operations for Royal Air Maroc -- was to cease operations until 1800 GMT, together with the smaller airport in the capital Rabat, the transportation ministry said in a statement.
Flights into and out of Tangiers, Tetouan, Essaouira, Agadir, Tan-Tan and Guelmin were also halted until 1800 GMT, the ministry said.
By mid-day in Spain, air traffic control agency Aena had given the all-clear to reopen four airports that were shut down earlier in the day on the Canary islands of Tenerife and La Gomera and at Badajoz in southwest Spain.
But the airports on the Canary Island of La Palma, and at Seville and Jerez in southern Spain remained closed.
In all, some 180 flights were cancelled in Spain as of 0900 GMT, Aena said.
Spain has also imposed overflight restrictions at altitudes between 20,000 and 35,000 feet (6,000 metres and 10,600 metres) in the skies over Seville, Madrid and Barcelona, Aena said.
The cloud of volcanic ash which affected Turkish airspace last month returned Tuesday forcing flight bans up to an altitude of 20,000 feet over the Dardanelles Strait and the country's European corner for four hours from 1200 GMT, the General Directorate of State Airports said in a statement on its website.
The major international airport at Istanbul however remained open.
"At the moment, there is nothing affecting Istanbul. We do not have a critical situation in our hands," a directorate spokesman told AFP on condition of anonymity.
Iceland's volcanologists explained that the ash in Europe's skies is left over from previous weeks and can travel around in the atmosphere due to winds.