The United States has announced that it will move an aircraft carrier, ships, and fighters to the eastern Mediterranean and provide Israel with additional equipment and ammunition.
It follows the attack by Hamas on southern Israel, which President Biden described as "unprecedented and abhorrent."
A spokesperson for US National Security stated that several US citizens were among the deceased. Israel claims more than 700 people have been killed and 100 kidnapped.
According to Palestinian officials, more than 400 people have been killed in Gaza as a result of Israeli airstrikes in retaliation.
The USS Gerald R. Ford aircraft carrier, a missile cruiser, and four missile destroyers are en route to the region, according to US defense secretary Lloyd Austin. The United States would also send fighter aircraft.
Further military aid to Israel would be sent in the coming days, the White House said, adding that the US was working to ensure that Israel's enemies would not attempt to seek advantage from the situation.
President Ebrahim Raisi of Iran has endorsed the Hamas assault, stating that Israel must be held accountable for endangering the region.
Hamas has claimed that Iran assisted it in carrying out its attack, which involved rockets, drones, paraglider-mounted militants, and hundreds of fighters breaching Israeli frontier fortifications in the Gaza Strip.
US Secretary of State Antony Blinken stated that the United States had not seen evidence of direct Iranian involvement, but that Iran had provided aid to the Gaza-based organization for years.
Mr. Blinken also stated that authorities were investigating reports that nationals of the United States had been involved in the attack.
"According to the reports that we have received, there are several Americans among the deceased. According to what he shared with a US television station on Sunday, "we are working very actively to verify those reports."
A number of other countries, including the United Kingdom, France, Ukraine, and Thailand, have also recorded deaths.
According to Mr. Blinken, "this is a massive terrorist attack that is gunning down Israeli civilians in their towns, in their homes, and as we have seen so graphically, literally dragging people across the border with Gaza." "Consequently, you can well picture the effect that is having all across Israel. And the entire world ought to be appalled by what it has witnessed."
There are still reports of missing people involving hundreds of people. Hersh Golberg-Polin, an American citizen and Israeli resident who was attending a music festival in the desert when it was attacked by extremists. According to his parents, who spoke to sources, he sent them two texts that said, "I love you" and "I am sorry."
Michael Herzog, Israel's ambassador to the United States, mentioned that he was under the impression that American citizens were among the soldiers and civilians kidnapped in southern Israel, but he did not have any further information on this matter.
Annually, the United States sends Israel, a close ally, billions of dollars in military aid. Since World War II, Israel has been the recipient of the most US foreign aid overall.
In the near future, the United Nations Security Council will convene in New York to discuss the violence in Israel and Gaza.