A State Department email seen by Reuters said it plans to offer transit options beginning on Friday "but it will take some period of time to schedule everyone seeking to depart."

" If you choose to take this departure assistance, transportation will be by air to Athens or Frankfurt, or sea from Haifa to Cyprus," it added.

Reuters had reported that expected routes include Tel Aviv to Athens. An announcement is expected later on Thursday, the sources said.

On Wednesday, United Airlines it would add two flights between Newark, New Jersey, and Athens in the coming days to help Americans trying to return home from Israel.

The State Department declined to comment.

The email seen by Reuters said "Americans will be asked to sign an agreement to repay the U.S. government prior to departure and should be prepared to arrange your own lodging and onward travel from Greece, Germany or Cyprus to your final destination."

United, American Airlines

Delta CEO Ed Bastian said the airline has been involved in discussions about supporting efforts to help Americans leave Israel.

"Right now, we're looking at providing some additional lift to Europe to get people out of Europe. But no, we don't have any plans to be flying into Israel," Bastian said on a company earnings call. "It's considered unsafe for a U.S. carrier to operate in that airspace currently."

Deputy Secretary of State Richard Verma held discussions with U.S. airlines this week about the issue, sources told Reuters.

The State Department said on Wednesday it was "exploring contract options to facilitate U.S. citizen travel to nearby countries."

Earlier this week, nearly 150 lawmakers led by U.S. Representatives Grace Meng and Nicole Malliotakis sent a bipartisan letter to Secretary of State Antony Blinken urging the department "to use all tools at its disposal help get Americans out of Israel and back home to the United States."

The letter asked for charter flights and military aircraft to be considered as options to help evacuate U.S. citizens.

(Reporting by David Shepardson; additional reporting by Rajesh Kumar Singh in Chicago; Editing by Richard Chang)

By David Shepardson and Steven Scheer