BRUSSELS – The Icelandic volcano with the unpronounceable name reminded the world again that it has the power to disrupt international travel — coughing out a spreading cloud of ash that delayed or canceled hundreds of flights between Europe and North America.

The prospects for flights today remained grim, with no improvement in sight for trans-Atlantic passengers, and with a plume of low-altitude ash continuing to float eastward over Spain and southern France.

Flights had to be rerouted north over Greenland or south around Spain to avoid the 1,200-mile-long cloud stretching from Iceland to northern Spain.

About 600 airliners make the oceanic crossing every day. Around 40 percent were rerouted southward and the rest skirted Iceland from the north, according to Eurocontrol.

The disruptions to air traffic did not compare to the five-day closure of European airspace last month, which forced the cancellation of more than 100,000 flights, stranded passengers around the world and caused airlines direct losses of more than $1.4 billion.

In Italy, the civil aviation authority ENAC said no flights would be allowed over a large swath of northern Italy today from 8 a.m. to 2 p.m. local time because of the cloud. Only the northeast corner of Italy was spared so far, leaving open the airports of Venice, Trieste and Rimini.

•  In Spain, 19 airports in the north, including the international hub Barcelona, were closed Saturday. The country’s airport authority said more than 670 flights had been canceled by 2 p.m. local time.

•  Likewise, 125 flights in and out of Portugal were canceled up to noon local time.

Aer Lingus canceled flights from the United States to Dublin, citing the exceptionally circuitous routes to get around the cloud.

On a normal day, European air traffic control centers handle between 26,000 and 30,000 flights. Until Eyjafjallajokul, the volcano in southern Iceland, stops its emissions, the future course of Europe’s ash crisis will depend heavily on the prevailing winds. The eruption of the glacier-capped volcano has shown no signs of stopping since it began belching ash April 13. It last erupted from 1821 to 1823.

Eurocontrol’s forecast chart of volcanic activity for early today showed a solid line of cloud extending from Greenland to the Azores and Madeira Islands in the mid-Atlantic, at altitudes up to 35,000 feet — right in the path of most trans-Atlantic flights. The Brussels-based air traffic management agency said the area of potential ash contamination was expanding in particular between the ground and 20,000 feet.

“Depending on the winds, the ash could impact south France and possibly north Italy tomorrow,” Eurocontrol spokeswoman Kyla Evans said Saturday.

In Paris, engineer Jerome Lecou of the national weather service Meteo France said the civil aviation authority was doing an evaluation with a sounding device-equipped aircraft to gather data in order to determine whether some airports should be closed.

He said it remained unclear whether the annual Cannes Film Festival, which opens Wednesday, would be affected by the flight disruptions.