The Keflavik International Airport and Reykjavík International Airport were closed beginning early April 23 morning, the aviation authority said, according to a statement on the Keflavik airport's website.

Though the ash cloud originated in Iceland, the country's airports have been spared from closure until now. Strong northwest winds had been blowing ash from the volcano, in the south of Iceland, out to sea and over Europe.

Two other Icelandic international airports, in Akureyri and Egilsstadir, will stay open to all air traffic, the aviation authority said. The ash cloud is not expected to reach those cities, which are in the north and east of the island nation.

Icelandair announced that trans-Atlantic passengers from the U.S. and Europe who would have stopped in Keflavik will be rerouted via Glasgow, Scotland.

Icelandair said that passengers traveling to and from Iceland will have the option of being re-routed through the Akureyri airport, a four-hour drive from Reykjavík. The airline is arranging bus travel between Akureyri airport and the Reykjavík Bus Terminal.