The Air Line Pilots Association (ALPA) -- which represents more than 74,000 pilots between 42 US and Canadian airlines, including majors like JetBlue, Delta, and United -- told members today its "working diligently" with carriers that fly to Israel to "ensure the safety of each of [its] members."

-ABC News' Amanda Maile

The White House has pledged assistance to Israel in responding to Hamas' attack -- and America has for decades maintained a vast pre-positioned military stockpile inside Israel.

First established in the wake of the Yom Kippur War of 1973, when it took time for the U.S. to send supplies to Israel, the munitions are available in case of emergencies.

It’s possible that Israel will ask the U.S. to tap into this stockpile, which contains weapons systems including tanks and ammunition stored in warehouses.

While not especially well known to the public, the supplies got some exposure earlier this year when the U.S. planned to use them in order to send artillery to Ukraine in responding to Russia's invasion.

-ABC News' Luis Martinez

Israeli rescue service Zaka said at least 260 bodies were removed from the venue of the music festival in southern Israel that came under a Hamas attack.

United Airlines said Sunday its Tel Aviv flights will remain suspended until conditions allow for them to resume.

The airline operated two scheduled flights out of TLV late Saturday and early Sunday.

"The safety of our customers and employees is our top priority," United said.

-ABC News' Amanda Maile

The United States is warning against other countries from becoming involved in the Israel-Gaza conflict amid fears that it could spread into a wider war in the Middle East.

"This is not the moment for other parties who are hostile to Israel to seek advantage or to seek to exploit the attacks that have taken place," Jon Finer, deputy national security adviser to U.S. President Joe Biden, Monday on "Good Morning America."

"That is part of why the United States has moved the Carrier Strike Group to the eastern Mediterranean to send a strong and unmistakeable signal that no one else should get involved in this," he added. "We'll see how things unfold in the course of the coming days."

Finer also emphasized that the U.S. believes "Israel has every right to defend itself full-stop."

"Israel will ultimately make the decisions about how it chooses to go about and conduct that defense," he said. "We are offering support in a number of ways."

Finer noted that "more U.S. steps to show support and solidarity for Israel" can be expected.

"The U.S. is going to offer support at every level for Israel's defense and we are working through details those details with our intelligence professionals, our military and our diplomats," he added. "We are in daily -- in fact, many times a day -- contact with Israeli counterparts to see what they need and offer it."

The U.S. "strongly suspect[s] that there will be American citizens among those killed" in the ongoing conflict, according to Finer.

"We are looking obviously very intensively into whether there were any Americans were among those who have been abducted and brought to Gaza. This is still ongoing," he said. "There is still fighting inside Israel as we speak and there is a bit of fog of war in terms of the ability to gather specific information. And so, we will have much more to say about this at the right time."

When asked for comment on a recent report by The Wall Street Journal that Iran was behind Hamas' latest attack on Israel, Finer responded: "We have no direct information to confirm that report. We've obviously seen it, we're looking into it, but we do not have the ability to corroborate it at this time."

"What we can be quite clear about is that Iran is broadly complicit in these attacks for having supported Hamas going back decades -- for having provided financial support, for having provided training, for having provided weapons to Hamas," he added. "What we don't have is direct information that shows Iranian involvement in ordering or planning the attacks that took place over the last couple days. It's something that we’re going to keep looking at closely."