Up to 50 Israelis who were being held hostage by Hamas have been freed, according to an Israel Defense Forces spokesperson.

They were being held in the dining hall of Kibbutz Be'eri in southern Israel, though the situation has been "neutralized," the IDF spokesperson said.

Officials still believe hostages are being held in Gaza but an exact number hasn't been released.

The FBI and the Department of Homeland Security have issued a "Public Safety Notification" to law enforcement around the U.S., urging them to remain vigilant and report any suspicious activity in the midst of the ongoing situation in Israel.

The notice says the agencies "do not currently have specific intelligence indicating a threat to the United States stemming from the Hamas attacks in Israel" but that "foreign terrorist organizations and their supporters remain committed to attacking the United States within and beyond our borders."

"In recent years, there have been several events and incidents in the United States that were purportedly motivated, at least in part, by the conflict between Israel and Hamas," the notice continued. "These have included the targeting of individuals, houses of worship, and institutions associated with the Jewish and Muslim faiths with acts of physical assault, vandalism, or harassment."

-ABC News' Mike Levine

A high-ranking Israel Defense Forces commander was killed in action Saturday, the military said.

Col. Jonathan Steinberg, 42, the commander of the Nahal Brigade, was killed during a confrontation with Hamas, IDF said.

United Hatzalah, a community-based volunteer EMS organization, said so far it has treated nearly 1,000 people for "various injuries" in southern and central Israel.

The organization said it has also transported an unspecified number of patients to hospitals in the regions via ambulance and helicopter.

As the Biden administration intensifies efforts to help American nationals leave Israel and Gaza, more than 20,000 U.S. citizens have reached out to the State Department asking for help in the wake of the Hamas attacks, including several hundred seeking to leave Gaza, according to two U.S. officials.

While not all have actively sought assistance with transportation, "many thousands" across Israel have indicated they needed help finding flights out of the country, the officials said.

Government-chartered planes have now started to ferry U.S. citizens from Israel to other countries in the region, though one official said the State Department still cannot share a detailed breakdown on the number of Americans whose departure it has already facilitated or the number of Americans still waiting for help "given this is an unfolding situation."

For Americans in Gaza, the U.S. is still eyeing the Rafah border crossing between Gaza and Egypt as a means of safe passage. Officials say they are very hopeful they will be able to work with Israel and Egypt to establish a corridor for U.S. citizens and other foreign nationals, but that it could take days to make substantial progress.

The Israeli government estimated that between 100 to 130 Americans were living in Gaza earlier this year. An official says the State Department believes hundreds more are visiting -- putting the total number in Gaza potentially between 500 and 600.

The State Department estimates that roughly 500,000 American citizens reside in Israel.

-ABC News' Shannon K. Crawford