White House spokesman John Kirby earlier told reporters the first charter flight that the state department organised had departed from Israel and was en route to Europe.

Kirby said the government is exploring departure options by sea as well. “We’re just trying to add to the options.”

Reuters identified the flight on a US-based charter company from flight records, and a White House official confirmed it had landed on the condition of anonymity.

Additional charter flights between Athens and Tel Aviv have been scheduled through at least Oct 19, a separate source said.

More than 400 Americans were signed up for the first flight but that figure includes an assumption that some would not turn up for the flight, a different source said.

On Wednesday, United Airlines said it would add two flights between Newark, New Jersey, and Athens starting on Thursday to help Americans trying to return home from Israel. The company also said it would add a third round trip. Delta Air Lines similarly said it would add flights to Athens in the coming days.

American Airlines said it has “seats available from European airports that offer capacity for connections from Israel and will continue to coordinate with the US Department of State on any additional capacity needs, either through operating larger aircraft or adding flights.”

A state department email on Thursday 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.” Americans traveling “will be asked to sign an agreement to repay the US government prior to departure,” the government added.

United, American, and Delta all temporarily halted direct flights to Israel.

Deputy secretary of state Richard Verma held discussions with US airlines earlier this week about the issue, sources told Reuters, adding that he told them the US government had received roughly 17,000 enquiries about travel assistance leaving Israel.