More than 40 commercial flights scheduled to enter and depart Puerto Rico have been canceled because of volcano ash hovering over the U.S. Caribbean territory.

Ports Authority spokeswoman Mariana Rodriguez says JetBlue, AirTran Airways, American Eagle and Continental were the majority of flights affected Tuesday night.

She said ash from the Soufriere Hills volcano in nearby Montserrat settling at 10,000 feet (3,000 meters) is causing poor visibility.

Rodriguez said operations at the Luis Munoz Marin International Airport in Isla Verde and the airports in Aguadilla and Ponce should return to normal by Wednesday.

She said 45 commercial flights and one cargo flight were canceled.