Israel's defense minister ordered a "complete siege" of Gaza on Monday, as the military said it had retaken control of Israeli communities that were stormed by Hamas gunmen over the weekend.
Yoav Gallant said on camera that Israel would halt the supply of electricity, food, water and fuel to the Palestinian enclave. "I have given an order - Gaza will be under complete siege," the minister said. "We are fighting barbarians and will respond accordingly."
Israeli forces are conducting "wide-scale strikes" on several "strategic" centers in Gaza belonging to Hamas, the Israel Defense Forces (IDF) said in a statement Monday.
Earlier, Israeli forces fought door-to-door to regain control of all communities around Gaza. There is no ongoing fighting between Israeli forces and Hamas militants inside Israel, the Israeli military said.
More than 48 hours have passed since the Islamist militant group launched a surprise assault, launching thousands of rockets and sending armed fighters into Israel.
Israel on Sunday formally declared war on Hamas in response to the unprecedented attack, which has so far killed more than 700 people in Israel. At least 2,506 people have been injured, the Israeli Health Ministry said.
Israeli jets continued to bombard Gaza with deadly airstrikes Monday as the war entered its third day.
The Israeli strikes have killed at least 560 people, including dozens of children, and left 2,900 injured, according to the Palestinian Ministry of Health.
Hamas said it fired 120 rockets toward the coastal cities of Ashdod and Ashkelon on Monday in response to Israeli airstrikes. A CNN team on the ground saw dust billowing over the sky, as rockets launched from Gaza were intercepted by the Israeli air defense system in Ashdod.
Nine United States citizens have died in the conflict, a US National Security Council spokesperson said.
Pleas for hostages' safe return
Hamas militants claimed late Sunday to be holding more than 100 hostages in Gaza, including high-ranking Israeli army officers, according to Mousa Abu Marzouk, chief deputy of Hamas' political bureau.
Videos on social media showed militants capturing multiple civilians, including children, as Israeli families across the nation made anxious pleas for the safe return of their loved ones.
In addition to Israeli captives, other nationalities are also believed to have been taken hostage, including American, Mexican, Brazilian and Thai nationals - further complicating Israel's response to the Hamas attack. At least nine citizens from Peru, Paraguay, Brazil and Mexico are missing, according to their respective authorities.
Qatar has been in talks with Hamas about the hostages the terror group is holding inside Gaza, and the US has been coordinating with the Qataris as they play a key mediating role with Hamas, a senior US official and another person familiar with the discussions told CNN.
CNN has reached out to the governments of Qatar and Israel for comment.
'Massacre' in Gaza
For now, airstrikes have been Israel's primary retaliation measure within Gaza itself, with jets repeatedly pounding the heavily populated 140 square mile coastal strip, turning multiple buildings to rubble, displacing tens of thousands of people and sending waves of injured Palestinians to overwhelmed hospitals.
An IDF spokesman said it had been hitting Hamas, destroying around 800 targets and killing "hundreds" of fighters, wounding thousands and capturing scores of others.
Most of those arriving at hospitals in Gaza have sustained second- and third-degree burns and amputations, a spokesperson for the Palestinian health ministry in Gaza told Palestinian news outlet Shihab Agency on Monday. Many have also sustained shrapnel injuries, Ashraf al-Qidra said.
Those seeking hospital care are mainly women and children, al-Qidra said, adding that this is a "result of Israelis directly targeting residential houses and buildings."
Access to medical care has been complicated by Israel cutting power to the territory, threatening the "lives of hundreds" of those injured, the Palestinian Ministry of Health in Gaza said.
The ministry said later that all services at the only functioning hospital in Gaza's Beit Hanoun neighborhood were suspended due to continuous Israeli airstrikes, blocking medical teams' ability to enter or exit the building. Nine ambulances have been targeted since Saturday, the ministry added.
Israeli airstrikes targeted the Shati and Jabalia refugee camps in Gaza on Monday, the Palestinian health ministry said, describing the assault as a "massacre against the entire neighborhood."
The ministry said bodies were still being recovered after the strikes killed a "large number" of people. No death toll has been provided.
Meanwhile, Palestinian Minister of Health Mai al-Kaila urged the international community to stop "the aggression" against medical facilities and teams in Gaza.
At least 13 family members, including four toddlers, were killed in an Israeli airstrike in Khan Younis in southern Gaza on Sunday, according to journalist Hassan Eslayeh and a family relative.
Sounds of battle
While it remains unclear what the full scale of the Israeli response will be, Prime Minister Benjamin Netanyahu on Sunday predicted a "long and difficult war" and vowed "mighty vengeance" on Hamas.
IDF spokesperson Lt. Col. Richard Hecht said Sunday that the priority for the coming hours and days was to "control the entire enclave and kill all the terrorists in our territory."
Israel's declaration of war set the stage for a major military operation in Gaza, and tanks and personnel carriers could be seen on the move near the Israel-Gaza border on Sunday.
Thousands of Israeli reservists have been called up and the IDF announced that several communities close to the Gaza security fence are being evacuated.
An Israeli military official and a United States defense official said Israel is requesting precision guided bombs and additional interceptors for its Iron Dome missile system from the US, including Joint Direct Attack Munitions, or JDAMs - a kit that turns an unguided "dumb" bomb into a precision "smart" weapon.
US Defense Secretary Lloyd Austin said the US would provide security assistance to Israel imminently. The US said it was also sending a Navy carrier strike group to the eastern Mediterranean Sea, including guided missile destroyers and guided missile cruisers.
Horror on the ground
Many Israelis have spent much of the past two days in bomb shelters and saferooms.
Throughout the bloody weekend, Hamas rockets made direct hits on multiple locations inside the country, including Tel Aviv, while armed terror groups entered Israel and infiltrated military bases, towns and farms, shooting at civilians and taking hostages.
The assault has left Israel reeling and impacted families far beyond its borders. Twelve Thai citizens, 10 Nepalis, two Ukrainians, two French nationals and one British citizen are among those killed in Israel.
Photos released by the Israeli foreign ministry showed dozens of bodies in the aftermath of Hamas gunmen's attack on a music festival near the Israel-Gaza border, which emergency responders said left at least 260 dead.
The father of an Israeli woman who was reportedly taken hostage at the festival told CNN that he "didn't want to believe it" when he saw his daughter being hoisted onto the back of a motorcycle by Hamas assailants in a video circulating on social media.
"One couldn't describe it with words. It's impossible... It was a very difficult moment," Yakov Argamani said, describing the moment he saw the video of his 25-year-old daughter Noa for the first time.
Videos obtained and geolocated by CNN show at least four civilians in the kibbutz of Be'eri were killed while in the custody of Hamas, just feet from where armed militants had been escorting them.
The IDF said early Monday that Be'eri was "very badly hit."
Regional concerns of escalation
Questions remain over how the Israeli military and intelligence apparatus appeared to be caught off guard in one of the country's worst security failures.
Fighting between the two sides has surged in the past two years. The violence has been driven by frequent Israeli military raids in Palestinian towns and cities, which Israel has said are a necessary response to a rising number of attacks by Palestinian militants on Israelis.
UN peacekeepers urged restraint after the conflict flared out into the wider region on Monday, when the IDF said it killed armed individuals who "infiltrated" Israel from Lebanon.
It came after Lebanese group Hezbollah claimed responsibility for targeting three Israeli sites in Shebaa Farms, which Lebanon considers Israeli-occupied. The al-Quds Brigades of the Palestinian Islamic Jihad later said it bombed several locations "in southern Lebanon on the border with occupied Palestine."
On Sunday, the UN Security Council held an emergency meeting but no action was taken afterward.
European Union foreign ministers are expected to meet Tuesday to address the situation in Israel.
