Secretary of State Antony Blinken and Israeli Prime Minister Benjamin Netanyahu sheltered in a bunker for five minutes with the war cabinet and the rest of their meeting participants after rocket sirens went off in Tel Aviv on Monday, according to State Department spokesperson Matt Miller.

The meeting has since been moved and participants are going to an Israel Defense Forces command center to continue their discussions, Miller said.

Blinken returned to Israel on Monday to meet with Netanyahu. Miller said earlier that Blinken discussed in their meeting his "firm support" of Israel's right to defend itself and efforts to provide humanitarian aid and free hostages.

-ABC News' Shannon Crawford

The Pentagon has placed about 2,000 American troops on a heightened state of readiness to possibly deploy to the Middle East if they're needed, a U.S. official confirmed. The Wall Street Journal first reported the news.

If these units are deployed, their purpose would be to serve as a deterrent.

-ABC News' Luis Martinez

The Israeli hostages in Gaza include an elderly women with Parkinson's disease, a 60-year-old man with multiple sclerosis and children with autism, according to the Israeli Hostages and Missing Families Forum.

Other hostages are suffering from amputated limbs and severe injuries from rape, the group said.

The hostages are "enduring extreme conditions as time runs critically short," the group said.

The International Committee of the Red Cross said its met with Hamas leadership and is pushing Hamas for immediate release of the hostages.

The Red Cross is also asking Hamas to allow access to the hostages to provide care and to permit hostages to communicate with their families.

-ABC News' Will Gretsky

An Israeli airstrike struck a road close to the Rafah border crossing and also hit a nearby United Nations Relief and Works Agency warehouse, according to an Egyptian military source.

This is the fourth strike near the border since the war began.

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