Gen. Erik Kurilla, the top U.S. military commander in the Middle East, has arrived in Israel.

"I’m here to ensure that Israel has what it needs to defend itself, and am particularly focused on avoiding other parties expanding the conflict," Gen. Kurilla said in a statement provided by U.S. Central Command.

Kurilla is set to conduct "high-level" meetings with Israel’s military leadership "to gain a clear understanding of Israel’s defense requirements" and outline American support efforts "to avoid expansion of the conflict."

-ABC News’ Luis Martinez

A State Department official said Monday night that the department has offered 4,000 American citizens and their immediate family members help to depart Israel via government-organized transportation since Friday.

“Since Oct. 13, we have augmented the limited commercial flight availability by offering more than 4,000 seats on U.S. government-chartered transport by air and sea to U.S. citizens and their immediate family members,” one official said. “We have communicated the availability of departure assistance options for U.S. citizens via targeted, individualized messaging as well as via broad public messaging.”

Departing flights, though, were not nearly at capacity, the official said.

“The departure options we have offered have generally departed at half capacity or less. Nearly 1,000 U.S. citizens and their immediate family members have departed on U.S. government-chartered transport,” an official said.

The official added that 3,000 other American citizens have told the State Department that they were able to leave Israel and the West Bank on their own.

-ABC News’ Shannon Crawford

President Joe Biden will visit Israel on Wednesday, Secretary of State Anthony Blinken announced on Monday night.

Blinken made the announcement following a lengthy meeting with Israel Prime Minister Benjamin Netanyahu.

A 21-year-old Israeli hostage appeared in a video released by Hamas on Monday.

Mia Schem's family confirmed to ABC News that she is the person who is speaking in the 78-second video.

It was not known when the video was filmed.

Schem's family was slated to hold a news conference Tuesday morning local time.

-ABC News' Christopher Looft and Ellie Kaufman

In remarks with Israeli Prime Minister Benjamin Netanyahu, Secretary of State Antony Blinken said at least 25 Americans had now been confirmed dead in Israel.

Netanyahu described some of the atrocities committed by Hamas.

"Hamas has shown itself to be an enemy of civilization: The massacring of young people in an outdoor music festival, the butchering of entire families, the murder of parents in front of their children and the murder of children in front of their parents. The burning of people alive, the beheadings," he said.

"Hamas should be treated exactly the way ISIS was treated," he said. "They shouldn't be spit out from the community of nations. No leader should meet them. No country should harbor them. And those that do should be sanctioned."

Blinken said he was speaking not only as an American diplomat, but as a Jew, a husband and a father of young children, saying it was impossible for him to look at photos of families killed "and not think of my own children."

"The same time that we've been shocked by the depravity of Hamas, we've also been inspired by the bravery of Israel citizens," he said. "The grandfather who drove over an hour to a kibbutz under siege, armed only with a pistol and rescued his kids and grandkids. The mother who died shielding her teenage son with her body, giving her life to save his -- giving him life for a second time."

Blinken remarked that some U.S. aid had already been delivered, and that more military aid was on his way. He said the administration would work with Congress to meet Israel’s additional needs and that bipartisan support for Israel was "overwhelming."

The secretary called on world leaders to condemn Hamas.

Blinken also reiterated that Israel "has the right -- indeed, the obligation -- to defend itself" but that it was "so important to take every possible precaution to avoid harming civilians."

-ABC News' Shannon Crawford