Israel-Gaza updates: Israeli forces preparing for 'wide range of offensive plans'

The U.S. Embassy said it'll offer transportation for Americans looking to leaving Israel beginning on Friday.

"It will take some period of time to schedule everyone seeking to depart," the embassy said. "Transportation will be by air to Athens or Frankfurt, or sea from Haifa to Cyprus. You will not be able to choose your destination – we will assign you to the next available flight or ship."

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US Embassy to help Americans evacuate from IsraelThe State Department estimates that roughly 500,000 American citizens live in Israel.

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"You should be prepared to depart within 8-12 hours of receiving notice of your booking. Each traveler may bring one small carry on item no more than 22 pounds (10 kg) and one suitcase no more than 35 pounds (16 kg)," the embassy said.

Delta Air Lines said it's partnering with the government to help set up flights through Athens.

United Airlines said it's adding extra flights with capped fares between Athens and Newark, New Jersey, and will use a larger plane for its Athens to Washington flight. "We’re in close touch with the U.S. State Department as it seeks to add additional options for Americans traveling from the region," United said.

American Airlines also said it is working "closely" with the State Department on its needs.

The U.S. expects "these initial travel options to facilitate the safe departure of thousands of U.S. citizens per week," State Department spokesperson Matthew Miller said in a statement.

A separate official said that the State Department remains in contact with "several thousand" American citizens in Israel, but it’s unclear how many will ultimately decide to leave. Some have already departed.

The State Department estimates that roughly 500,000 American citizens live in Israel.

-ABC News' Amanda Maile, Will Gretsky and Shannon Crawford

As Hamas militants launched an unprecedented attack on Israel over the weekend, pillaging, kidnapping and killing civilians across several towns, one of the first targets was the Supernova music festival, held in the Negev desert in southern Israel.

At least 260 people were killed, making it one of the worst civilian casualty incidents in Israel's history.

ABC News talked to survivors and families of the missing, and analyzed and verified witness video and security footage to piece together how the brutal killings unfolded.

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Israel music festival massacre timeline: How night of dancing ended in tragedyABC News talked with survivors and families of the missing in addition to analyzing and verifying witness video and security footage to piece together how the brutal killings at the Supernova Music Festival unfolded.

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As the humanitarian crisis worsens in Gaza, Israeli Energy Minister Israel Katz said no electrical switch will be turned on, no water tap will be opened and no fuel truck will enter Gaza until the Israeli hostages are returned home.

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‘Devastating’ humanitarian crisis unfolding in GazaAt least 330,000 people in Gaza have been displaced from their homes since Israel unleashed retaliatory air strikes, the United Nations said.

Reuters

Gaza relies on Israel for most of its power, which was cut off following the attack. Its sole power plant ran out of fuel on Wednesday.

The White House said there are no intentions to send U.S. troops to Israel.

"The Israelis have made it very clear that they don't want foreign troops on their soil. That they want to prosecute these operations on their own and they have every right to want to do that," said John Kirby, spokesperson for the National Security Council.

Kirby said the U.S. would "do everything we can to improve" the capabilities of the Israeli military.

And as humanitarian concerns grow in Gaza, Kirby told reporters that there are "ongoing conversations" with Israeli counterparts about the need for the "continued flow of humanitarian assistance" to the area.

-ABC News' Justin Gomez and Molly Nagle