The head of the American Airlines pilots union said on Monday that its members should not fly to Israel until it is clear the situation is safe. Ed Sicher, president of the Allied Pilots Association, said in a statement: "It is not prudent or appropriate to knowingly put our crews and passengers in danger by sending an aircraft into a war zone. I am directing all pilots to halt flights to Israel until we can reasonably ensure the safety of the area."

Citing a travel advisory issued by the U.S. State Department on Sunday, Siegel said the situation in Israel is unpredictable and "mortar and rocket attacks can occur without warning." He also said the U.S. Federal Aviation Administration (FAA) issued an Air Mission Notice (Notam) telling operators to use extra caution.

"Until further notice, if you are scheduled, assigned or reassigned to Israel, please call your chief pilot or IOC duty pilot to decline the assignment. Inform them that you are declining this assignment in accordance with guidance and warnings issued by the State Department and FAA," Siegel said.

Prior to this, a number of international airlines had announced the suspension of flights to Israel, including Air India and Cathay Pacific. This comes after attacks broke out around the Gaza Strip on Saturday morning, killing more than 700 Israelis. Some 400 Palestinians have been killed in fighting and reprisal attacks.