NEW YORK (AP) — Major airlines have suspended flights to Israel after the nation declared war following a massive attack by Hamas.

American Airlines, United Airlines and Delta Air Lines suspended service as the U.S. State Department issued travel advisories for the region citing potential for terrorism and civil unrest.

American suspended service to Tel Aviv through Friday. The airline said that it has issued a travel alert providing additional flexibility for customers whose travel plans are impacted.

“We continue to monitor the situation with safety and security top of mind and will adjust our operation as needed,” American said.

United said it allowed two scheduled flights out of Tel Aviv late Saturday and early Sunday and accommodated its customers, crews and employee travelers who were at the airport. The airline said that its Tel Aviv flights will remain suspended until conditions improve.

Delta said its Tel Aviv flights have been canceled into this week. The airline said it’s monitoring the situation and making schedule adjustments accordingly. The company said customers with canceled flights or who want to change their Tel Aviv ticket should check the Delta app, website or call Delta reservations to make adjustments.