Major US airlines have cancelled flights into and out of Israel.
At least 11 Americans have died in the violence in Israel, President Joe Biden said on the third day since Palestinian militants launched a stunning attack on Israel.
In a statement, Biden described the deaths as the “heart-wrenching” results of an “appalling terrorist assault against Israel.”
He said the US believed that the Hamas militant group was likely holding American citizens as prisoners.
He added that the US is working with Israel to handle the hostage crisis.
“This is not some distant tragedy,” the president said in his statement.
“The ties between Israel and the United States run deep. It is personal for so many American families who are feeling the pain of this attack,” the president added.
The identities of the dead Americans were not immediately released, and it was unclear if any were from New York, home to about 1.6 million Jews.
In New York City, there was a heavy police presence at synagogues on Monday.
Major US airlines have cancelled flights into and out of Israel.
According to a count by Rep. Grace Meng’s office, at least 50 New York residents were seeking to return from Israel on Monday.
The State Department said it was in contact with the families of the dead Americans.
More than 1,300 people have already been reported dead in the conflict, which was escalating Monday as Israel ordered an intense retaliatory assault on the blockaded Gaza Strip.
At least 700 people have died in Israel, according to the Israel Defence Forces.
The Palestinian death toll was 687, the Palestinian Health Ministry said Monday.
Meng, a Democrat who represents much of central and eastern Queens, wrote a letter to the State Department asking it to “use all resources at its disposal” to help Americans in Israel return to the U.S.
A spokesman for Meng, Jordan Goldes, said a “handful” of Meng’s constituents were in Israel.
Senate Majority Leader, Chuck Schumer, a Brooklyn Democrat, said in a statement late Sunday night that he had been briefed on the rising American death tally – then four – and that it would rise.
“The viciousness and brutality of this unprecedented attack from Hamas targeting innocent civilians – children, families, seniors – is overwhelming and heart wrenching,” added Schumer, who is Jewish and is currently on a trip to China.
Schumer met with China’s President, Xi Jinping on Monday and urged China to stand with the US in a united front in support of Israel, Schumer’s office said.
Schumer’s spokesman, Angelo Roefaro, said the majority leader convinced Xi to strengthen a statement opposing violence against civilians in Israel.
New York City is home to the largest Jewish population of any city on the globe.
It also has a significantly smaller Palestinian population; the exact size is not clear, but could number in the tens of thousands.
One New York City congressman, Dan Goldman, was in Israel when the fighting began, having made a trip for a family Bar Mitzvah, his office said.
Goldman and his family “sheltered from Hamas rocket fire in their hotel’s interior stairwell until early Sunday morning,” his spokesman, Simone Kanter, said in a statement.
Goldman, who represents lower Manhattan and sections of Brooklyn, returned to New York City on Sunday afternoon, Kanter said.
In response to the attacks by Hamas, Israel’s military struck more than 1,200 targets in the Gaza Strip between Saturday and Monday morning, according to the Israel Defense Forces.
The IDF said it hit another 1,200 targets on Monday.
In a speech that his office published on social media, Prime Minister Benjamin Netanyahu of Israel said that “Hamas will understand that by attacking us, they have made a mistake of historic proportions.
“We will exact a price that will be remembered by them, and Israel’s other enemies, for decades to come,” Netanyahu declared.
Some Israelis have been taken hostage by Hamas militants, according to Israel.
In his statement, Biden said, “The safety of American citizens — whether at home or abroad — is my top priority.”
“I have directed my team to work with their Israeli counterparts on every aspect of the hostage crisis,” Biden added.
He said the directive included “sharing intelligence and deploying experts from across the United States government to consult with and advise Israeli counterparts on hostage recovery efforts.”
