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Iranian backed Hamas terrorists invaded areas of southern Israel as rocket barrages launched from the Gaza Strip struck the area on Saturday, killing at least 100 Israelis in an attack the Islamist movement Hamas is taking responsibility for.

A senior Hamas military commander, Mohammad Deif, announced the start of the operation in which he called on Palestinians everywhere to attack the Israelis, saying in a broadcast on Hamas media that the group launched 5,000 rockets and calling the attack "the day of the greatest battle to end the last occupation on earth."

Local Israeli media reported that at least 100 people have been killed in the wide-ranging assault, while Gaza health officials say that 198 Palestinians have died in Israeli air strikes made in response to the Hamas attack. Hospitals are treating at least 985 wounded people, including 77 who were in critical condition, the Associated Press reported based on public statements and calls to hospitals. 

The IDF announced it would mobilize its forces in response to the attacks, confirming that Hamas has taken hostages and held prisoners of war in Gaza. Israeli military forces have moved troops to the Gaza border, where gunfire has already started as the forces move towards each other, Fox News correspondent Trey Yingst reported from Israel.

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Smoke rises after a rocket fired from the Gaza Strip hit a house in southern Israel

Smoke rises after a rocket fired from the Gaza Strip hit a house in Ashkelon, southern Israel, Saturday, Oct. 7, 2023. The rockets were fired as Hamas announced a new operation against Israel. (AP)

In a video message early Saturday morning, Israel Prime Minister Benjamin Netanyahu said, "Citizens of Israel, we are at war — not in an operation, not in rounds — at war."

Ambulance crews responded to areas around the Gaza Strip, and sirens sounded across Israel. Soroka Medical Center in Beer Sheva, the largest town in southern Israel, is treating 140 wounded, including 20 in serious and critical condition. Some of these wounded people are civilians. Another hospital in Ashkelon is treating 94 victims wounded in various conditions.

According to Israeli media, gunmen opened fire on passersby in the southern Israeli town of Sderot, and footage of the fighting appeared to show attacks in city streets: "A number of terrorists have infiltrated into Israeli territory from the Gaza Strip," the Israeli military said in a statement. 

Residents in the area surrounding the Gaza Strip are urged to remain in their homes.

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Israeli firefighters extinguish fire

Israeli firefighters extinguish fire after a rocket fired from the Gaza Strip hit a parking lot in Ashkelon, southern Israel, Saturday, Oct. 7, 2023. (AP)

"The Israeli Defence Forces will defend Israeli civilians and the Hamas terrorist organization will pay heavy price for its actions," the military said.

Netanyahu's office said he would meet top security officials in the coming hours to address the operation.

The sound of rocket launches could be heard in Gaza as residents reported armed clashes along the separation fence with Israel, near the southern town of Khan Younis. The residents said they had seen significant movement of armed fighters.

U.S. National Security Council Spokesperson Adrienne Watson "unequivocally" condemned the attacks, calling them unprovoked and stressing that "There is never any justification for terrorism." 

"We stand firmly with the Government and people of Israel and extend our condolences for the Israeli lives lost in these attacks," Watson wrote in a statement released Saturday morning. "National Security Advisor Jake Sullivan has spoken to Israeli National Security Advisor Tzachi Hanegbi and we remain in close contact with our Israeli partners."

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Rockets are fired toward Israel

Rockets are fired toward Israel from the Gaza Strip, Saturday, Oct. 7, 2023. (AP)

U.S. Chargé d’Affaires a.i. at the U.S. Embassy in Jerusalem, Stephanie L. Hallett, wrote on X, "Sickened by the images coming out of southern Israel of dead and wounded civilians at the hands of terrorists from Gaza. The United States stands with Israel."

European leaders are condemning the Hamas attack and voicing strong support for Israel. The head of the European Union’s executive commission, Ursula von der Leyen, wrote on X, formerly known as Twitter, on Saturday that the attack "is terrorism in its most despicable form." She said that "Israel has the right to defend itself against such heinous attacks."

German Chancellor Olaf Sholz said the terrorist rocket fire and rising violence "shock us deeply." He added that "Germany condemns these attacks by Hamas and stands beside Israel." 

French President Emmanuel Macron wrote that he "firmly" condemns the "terrorist attacks" against Israel and expressed "my full solidarity with the victims, their families and their loved ones."

Palestinians celebrate a destroyed Israeli tank

Palestinians celebrate by a destroyed Israeli tank at the Gaza Strip fence east of Khan Younis southern Saturday, Oct. 7, 2023. The militant Hamas rulers of the Gaza Strip carried out an unprecedented, multi-front attack on Israel at daybreak Saturday, firing thousands of rockets as dozens of Hamas fighters infiltrated the heavily fortified border in several locations by air, land, and sea and catching the country off-guard on a major holiday.  (AP Photo/Hassan Eslaiah)

British Prime Minister Rishi Sunak said he was "shocked" by the attacks. "Israel has an absolute right to defend itself," he posted on X. 

Dozens of IDF fighter jets were seen delivering strikes to a number of targets belonging to the Hamas terrorist organization in the Gaza Strip.

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In accordance with assessments by Israel's defense establishment, Minister of Defense Yoav Gallant has announced a "special security situation" in Israel’s homefront, within a 0-80 km radius from the Gaza Strip that enables the IDF to provide civilians with safety instructions and close relevant sites.

There has been fighting between Israel and Gaza in years past, and the fighting that started on Saturday is expected to last several days.

Fox News' Trey Yingst and Yonat Frilingm Peter Aitken, the Associated Press and Reuters contributed to this report.