Police in New York, where there are locations sensitive to both Israeli and Palestinian interests, are adjusting patrols in response to the situation in Israel.

"The NYPD's Counterterrorism and Intelligence Division consistently work at a level of high alert. When events from around the world could possibly affect NYC or we get Intel on a threat to NYC, we always increase our presence around houses of worship and certain areas when these conflicts arise," the NYPD said in a statement.

The Beverly Hills Police Department also said it increased security and patrols around Jewish institutions in the City and continues to work closely with law enforcement partners in the region to ensure public safety.

Law enforcement and Homeland Security officials will be assessing the potential for residual violence in the U.S.

Increased security around Jewish facilities and on university campuses -- particularly where there is a history of confrontational interactions -- is to be expected. Increased attention is expected to be paid to potential cyber threats and online activities intended to inspire violence by Iran, Hezbollah and other extremists threat actors.

-ABC News' Aaron Katersky and Alex Stone

United Airlines, American Airlines and Delta Airlines announced they will suspend operations to Israel Saturday night following unrest in the region. After two departures scheduled for Saturday, United's future operations will be suspended until conditions allow them to resume, the airline said.

"The safety of our customers and crew is our top priority. We are closely monitoring the situation and we are adjusting flight schedules as required," the carrier told ABC News.

American Airlines said it will temporarily suspended operations to and from Tel Aviv and will continue to monitor the situation, adjusting its operations as needed.

"American Airlines has temporarily suspended operations to and from Tel Aviv, Israel (TLV) [Saturday] and [Sunday], and has issued a travel alert providing additional flexibility to customers whose travel plans are affected. We will continue to monitor the situation with safety and security top of mind and will adjust our operation as needed," American Airlines said in a statement.

Delta Air Lines has canceled scheduled flights in and out of Tel Aviv this weekend. The airline said its working to "safely transport Delta people back to the U.S. and will work with the U.S. government as needed to assist with the repatriation of U.S. citizens who want to return home."

-ABC News' Amanda Maile and Sam Sweeney

President Joe Biden spoke with Israeli Prime Minister Benjamin Netanyahu, telling him that the U.S. "condemns" Hamas' assault on Israel.

"I made clear to Prime Minister Netanyahu that we stand ready to offer all appropriate means of support to the Government and people of Israel. Terrorism is never justified. Israel has a right to defend itself and its people. The United States warns against any other party hostile to Israel seeking advantage in this situation. My Administration’s support for Israel’s security is rock solid and unwavering," Biden said in a statement.

Biden also extended his condolences for lives lost and wished those wounded a "swift recovery."

"My team and I are tracking this situation closely, and I will remain in close touch with Prime Minister Netanyahu," Biden said.

U.S. Secretary of State Antony Blinken issued a statement condemning Hamas' attack on Israel, saying the U.S. will "remain in close contact with our Israel partners."

"The United States unequivocally condemns the appalling attacks by Hamas terrorists against Israel, including civilians and civilian communities. There is never any justification for terrorism. We stand in solidarity with the government and people of Israel, and extend our condolences for the Israeli lives lost in these attacks," Blinken said in a statement.

-ABC News' Shannon Crawford

National Security Council spokesperson John Kirby avoided saying if the U.S. believed Israel's calls for civilians in Gaza to evacuate in the next 24 hours was possible but acknowledge that it was a "tall order" given how densely populated the area is.

"Well, I think we're going to be careful not to get into armchair quarterbacking the tactics on the ground by the IDF. What I can tell you is we understand what they're trying to do. They're trying to move civilians out of harm's way and giving them fair warning. Now, it's a tall order. It's a million people, and it's a very urban, dense environment, already a combat zone. I don't think anybody's underestimating the challenge here of affecting that evacuation," Kirby said in an interview on CNN Friday morning.

"But it's pretty clear that what they're trying to do is to the maximum extent possible avoid civilian casualties and also separate Hamas from the human shields. I mean, Hamas actually gave a counterorder telling Palestinians in Gaza to stay at home. Why? Because having human shields, they think, protects them," Kirby continued.

Asked about their efforts to secure a safe passage for civilians out of Gaza, Kirby reiterated that the U.S. is talking to Israel and Egypt but would not comment further on progress.

On the Rafah crossing specifically, Kirby said "So far it's still closed. But that doesn't mean were not going to still try as hard as we can to talk to the Israelis and Egyptians about getting it open and having some sort of safe passage out. It's important that we also continue to work to make sure that humanitarian assistance can get in. The United States has no intention of stopping our efforts to continue to deliver humanitarian assistance, but there has to be a path in, there has to be a path out."

Kirby had no update on the Americans who are believed to be held hostage in Gaza and could not confirm reports that 13 hostages have been killed by Israeli airstrikes, as Hamas has claimed.

-ABC News' Molly Nagle