Biden to update Americans on Hamas attacks on Israel, fate of US citizens

President Joe Biden on Tuesday will give an update to the American people on the attacks in Israel as the violent coNFLict enters its fourth day.

Biden will speak at 1 p.m. ET at the White House, which was lit up in blue and white on Monday evening in a show of support for Israel after Hamas launched a surprise air, sea and land incursion over the weekend.

Israel since declared a state of alert for war and has been sending retaliatory airstrikes to Gaza. The number of people killed on both sides is mounting, with more than 900 dead in Israel and more than 700 dead in Gaza.

Biden confirmed at least 11 Americans have been killed in the fighting and more may be among the hostages taken by Hamas in a statement on Monday calling the developments “heart wrenching.”

"The safety of American citizens -- whether at home or abroad -- is my top priority as President," Biden said.

White House national security spokesman John Kirby, on ABC's “Good Morning America” Tuesday, said the administration is preparing for the “distinct possibility” more Americans were killed.

Kirby, though, didn’t have any specific information on if Americans are being held hostage but emphasized the U.S. is in close contact with Israel and has offered assistance through intelligence, information and hostage recovery expertise.

But asked by ABC’s George Stephanopoulous if the U.S. would be willing to make a deal for any Americans who may be being held by Hamas, Kirby only said he “didn’t want to get too far ahead of where we are.”

“Clearly, the safety and security of Americans are a top priority for President Biden, we’ve seen that in the past,” Kirby said. “We’ll continue to work on this hard and if there are Americans that are being held hostage we’ll do everything possible to get them home to their families where they belong.”

The administration is boosting munitions to Israel, and the USS Gerald R. Ford aircraft carrier was sent toward Israel -- a move a senior U.S. defense official said was intended to be a deterrent to Iran and Hezbollah.

Iran has denied involvement in the Hamas attacks on Israel, and the U.S. and Israel have also said they don't have hard evidence linking Iran to the incursion.

Kirby on GMA was pressed about the threat of a second front opening up in the conflict if Hezbollah -- also designated a terrorist group by the U.S. and other nations -- were to engage.

"It remains unclear. Obviously, we are concerned about the possibility that now a northern front could be opened up if Hezbollah decides to get engaged," Kirby said. "Now, there's been some exchange of rocket fire, George, but no signs that they're all in as it as it were. So, we're watching this very, very closely."

Ahead of his remarks, Biden and Vice President Kamala Harris will meet with their national security teams to get an update and "give directions on next steps." Biden and Harris will also speak with Israel Prime Minister Benjamin Netanyahu.