LIVE | Day 5: Death toll crosses 3,600; Gaza power plant runs out of fuel

Some of these Israelis abroad are yearning to serve, whether that means fighting in a military reserve unit or volunteering to shuttle supplies to those in need, even as the war has already claimed at least 1,800 lives and shows no signs of abating.

Yaakov Swisa, a 42-year-old father of five, said nobody called and asked him to return to Israel to fight, but he feels he has no choice. He served for 15 years, and he said he learned that his army roommate was among at least 260 killed at a music festival.

Swisa wants to rejoin his reserve unit, even if that means leaving his family and his construction-business job in Los Angeles.

“I've been crying for two, three days. Enough. That's it. I am ready to fight," he said. “What else would I do ... while my friends are being buried in Israel?”

In some cases, Israelis who are too young to serve in the military, as well as non-Israelis with close ties to the country, have been trying to travel to assist family members or volunteer.

Adam Jacobs, an 18-year-old community college student in New Jersey, said he was born and raised in the US and for years travelled every summer to visit family in Israel. He said he learned his cousin was among those killed, and he wants to make his way to Israel to take on volunteer work, possibly shuttling supplies.

“I couldn't live with myself if I stayed here,” Jacobs said. “It's never been this bad.”

Travel has been challenging, with major airlines suspending flights in and out of Israel. The US State Department issued travel advisories for the region. Some reservists in the United States, home to more than 140,000 people born in Israel, were trying to get on charter flights.

Ofer Cohen, a New York businessman, said he learned there were more than 200 reservists travelling through South America on vacation at the time of the attacks. They've been called back to base but are unable to get there, thanks to cancelled flights. So Cohen is trying to cobble together hundreds of thousands of dollars to hire a plane to pick them up, as WhatsApp messages describing their troubles keep rolling in.

In Greece, hundreds of people waited hours to board emergency flights at Athens International Airport, many without a ticket and most travelling from other European destinations after cutting holiday and work trips short. As officers patrolled the area to provide security, volunteers handed travellers apples, bananas, and bottled water.

Israel Lawrence, 27, was born in Israel and grew up in London. He said that although he hasn't been formally called up, he's making the trip to join his fellow soldiers, many already on the front lines, and help his family members, who are living in terror and chaos.

“I want to be honest with you, I'm scared," said Lawrence, a trained rifleman who was on his way to Israel via Cyprus. "All the guys I'm with are terrified, but we are trained, and we'll do the best we can.”

This is the scene confronting Israel's military as it battles to beat back the sweeping assault launched by Hamas from the Gaza Strip.

“You see the babies, the mothers, the fathers in their bedrooms and how the terrorists killed,” Maj. Gen. Itay Veruz, a 39-year veteran of the Israeli army who led forces that reclaimed the village from militants, said on Tuesday (October 10) as he stood amid the wreckage.

“It's not a battlefield. It's a massacre.”

The Israeli military led a group of journalists, including an Associated Press reporter, on a tour of the village on Tuesday, a day after retaking it from what they said was a group of about 70 Hamas fighters.

Kfar Aza, surrounded by farms and just a few minutes down a country road from the heavily fortified fence Israel erected around Gaza, is one of more than 20 towns and villages attacked by Palestinian fighters early Saturday (October 7). Before the attack, the kibbutz, whose name means “Gaza village” in English, was a modestly prosperous place with a school, a synagogue, and a population of more than 700.

Walking through what is left provides chilling evidence of its destruction.

On the town's perimeter, the gate that once protected residents had been blasted open. Inside the settlement, the doors of many homes had been blown from their hinges by militants using rocket-propelled grenades. Throughout the town, walls and torched cars are riddled with bullet holes, tracing a path of violence that continues inside to bedrooms with mattresses spattered in blood, safe rooms that could not withstand the attack, even bathrooms.

By the time journalists were escorted into the town on Tuesday, rescuers had already removed the bodies of most of the villagers killed in the attack. But reporters watched as crews carried several more bags containing bodies to a truck and then to a lot in front of Kfar Aza's synagogue, where workers attached name tags.

Veruz, retired from the military for eight years before he was recalled on Saturday (October 7), said the scene was unlike anything he had ever witnessed, even in a country where violent clashes with Hamas and other militant groups are frequent. A military spokesman, Maj. Doron Spielman, agreed, comparing the toll in Kfar Aza and nearby villages he visited to scenes he witnessed as a New Yorker after the September 11, 2001 terrorist attacks.

“I remember going through 9/11 and waking up the next day, the next week, and everything had changed,” he said. “It's the same thing again. But worse because we're such a small country.”

Biden also said it was Hamas’ stated purpose to annihilate the state of Israel and kill Jewish people.

“There are moments in this life – and I mean this literally – when pure, unadulterated evil is unleashed on this world. The people of Israel lived through one such moment this weekend. The bloody hands of the terrorist organisation Hamas – a group whose stated purpose for being is to kill Jews,” Biden said in his address to the nation from the White House.

The US president has earlier vowed his administration's "rock solid and unwavering" support to Israel. The United States has launched a major global diplomatic drive to garner support for Israel and take necessary action against Palestinian militant group Hamas.

“We have said since the beginning that Iran is complicit in this attack in a broad sense because they have provided the lion's share of the funding for the military wing of Hamas. They have provided training. They have provided capabilities. They have provided support and they have had engagement and contact with Hamas over years and years,” US National Security Advisor Jake Sullivan told reporters on Tuesday.

“All of that has played a role in contributing to what we have seen. Now, as to the question of whether Iran knew about this attack in advance or helped plan or direct this attack, we do not, as of this moment I'm standing here at the podium, have confirmation of that. We are talking to our Israeli counterparts on a daily basis about this question,” he said.

The NSA said the US is trying to gather from its intelligence holdings on whether they have any further information on that. “We're looking to acquire further intelligence. And if there's an update to that, I'll share it with you,” Sullivan said. “While Iran plays this broad role, sustaining a deep and dark role in providing all of this support and capabilities to Hamas, in terms of this particular gruesome attack on October 7th, we don't currently have that information. We will continue to look for it,” he added.