Some U.S. and other international airlines are keeping a halt on flights to major Middle Eastern airports as global carriers scramble to figure out whether to continue flying to the region amid intensifying conflict between Israel and Iran and military intervention by the U.

Singapore Airlines customers who booked their flights directly can use the airline’s Assistance Request Form to seek a refund.

Commercial airlines around the world on Monday were weighing how long to suspend Middle East flights as a conflict which has already cut off major flight routes entered a new phase after the U.S. attacked key Iranian nuclear sites and Tehran vowed to defend itself.