Italy closed a large part of its airspace in the north of the country until at least the early afternoon on Sunday to counter the risk posed by volcanic ash coming from Iceland, the civil aviation authority ENAC said. The block on flights began at 0600 GMT (0800 local time) and was expected to last until at least 1200 GMT.
The closure would not affect the airspace in the eastern part of northern Italy and the airports of Venice, Trieste and Rimini would remain open, ENAC said.
A bulletin issued on Sunday by the Volcanic Ash Advisory Centre said the ash was expected to stay over Italy until Sunday evening.
Several Spanish airports in northern Spain including Barcelona reopened on Sunday after being shut on Saturday as a precaution against the ash cloud. The Spanish civil aviation authority said only three airports remained closed, all in the north-western region of Galicia, and that these might open from about 0900 GMT. They were Santiago, La Coruna and Vigo.
Some 24,500 flights were expected to take place in Europe on Sunday, about 500 below average for this time of year due to the ash, European air traffic agency Eurocontrol said in Brussels.