Backed by a barrage of rockets, dozens of Hamas militants broke out of the blockaded Gaza Strip and into nearby Israeli towns, killing dozens and abducting others in an unprecedented surprise early morning attack during a major Jewish holiday Saturday. A stunned Israel said it is now at war with Hamas and launched airstrikes in Gaza, vowing to inflict an “unprecedented price.”

In an assault of startling breadth, Hamas gunmen rolled into as many as 22 locations outside the Gaza Strip, including towns and other communities as far as 15 miles (24 kilometers) from the Gaza border. In some places, they roamed for hours, gunning down civilians and soldiers as Israel’s military scrambled to muster a response. Gunbattles continued well after nightfall, and militants held hostages in standoffs in two towns.

Israel’s national rescue service said at least 200 people were killed and 1,100 wounded, making it the deadliest attack in Israel in decades. At least 198 people in the Gaza Strip have been killed and at least 1,610 wounded in Israeli strikes, the Palestinian Health Ministry said. Hamas fighters took an unknown number of civilians and soldiers captive into Gaza, a deeply sensitive issue for Israel.

The conflict threatened to escalate to an even deadlier stage with Israel’s vows of greater retaliation. Previous conflicts between Israel and Gaza’s Hamas rulers brought widespread death and destruction in Gaza and days of rocket fire on Israeli towns. The situation is potentially more volatile now, with Israel’s far-right government stung by the security breach and with Palestinians in despair over a never-ending occupation in the West Bank and suffocating blockade of Gaza.

After nightfall, Israeli airstrikes in Gaza intensified, flattening several residential buildings in giant explosions, including a 14-story tower that held dozens of apartments as well as Hamas offices in central Gaza City. Israeli forces fired a warning just before, and there were no reports of casualties.

Soon after, a Hamas rocket barrage into central Israel hit four cities, including Tel Aviv and a nearby suburb, where two people were seriously injured. Throughout the day, Hamas fired more than 3,500 rockets, the Israeli military said.

The strength, sophistication and timing of the Saturday morning attack shocked Israelis. Hamas fighters used explosives to break through the border fence enclosing the Mediterranean territory, then crossed with motorcycles, pickup trucks, paragliders and speed boats on the coast.

In some towns, a trail of civilians’ bodies lay where they had encountered the advancing gunmen. On the road outside the town of Sderot, a bloodied woman slumped dead in the seat of her car. At least nine people gunned down at a bus shelter in the town were laid out on stretchers on the street, their bags still on the curb nearby. One woman, screaming, embraced the body of a family member sprawled under a sheet next to a toppled motorcycle; as she was led away, she picked up the dead person’s helmet from the ground nearby.

Associated Press photos showed an abducted elderly Israeli woman being brought back into Gaza on a golf cart by Hamas gunmen and another woman squeezed between two fighters on a motorcycle. Images also showed fighters parading captured Israeli military vehicles through Gaza streets.

"We are at war,” Israeli Prime Minister Benjamin Netanyahu said in a televised address, declaring a mass army mobilization. “Not an ‘operation,’ not a ‘round,’ but at war.”

“The enemy will pay an unprecedented price,” he added, promising that Israel would “return fire of a magnitude that the enemy has not known.”

The shadowy leader of Hamas’ military wing, Mohammed Deif, said the assault was in response to the 16-year blockade of Gaza, Israeli raids inside West Bank cities over the past year, violence at Al Aqsa - the disputed Jerusalem holy site sacred to Jews as the Temple Mount - increasing attacks by settlers on Palestinians and growth of settlements.

“Enough is enough,” Deif, who does not appear in public, said in the recorded message. He said the attack was only the start of what he called “Operation Al-Aqsa Storm” and called on Palestinians from east Jerusalem to northern Israel to join the fight. “Today the people are regaining their revolution.”

The Hamas incursion on Simchat Torah, a normally joyous day when Jews complete the annual cycle of reading the Torah scroll, revived painful memories of the 1973 Mideast war practically 50 years to the day, in which Egypt and Syria launched a surprise attack on Yom Kippur, the holiest day of the Jewish calendar, aiming to take back Israeli-occupied territories.

Comparisons to one of the most traumatic moments in Israeli history sharpened criticism of Netanyahu and his far-right allies, who had campaigned on more aggressive action against threats from Gaza. Political commentators lambasted the government over its failure to anticipate what appeared to be a Hamas attack unseen in its level of planning and coordination.

Asked by reporters how Hamas had managed to catch the army off guard, Lt. Col. Richard Hecht, an Israeli army spokesman, replied, “That’s a good question.”

The abduction of Israeli civilians and soldiers also raised a particularly thorny issue for Israel, which has a history of making heavily lopsided exchanges to bring captive Israelis home.

Hamas’ military wing claimed it was holding dozens of Israeli soldiers captive in “safe places” and tunnels in the Gaza Strip. The Israeli military confirmed that a number of Israelis were abducted but would not give a figure. If true, the claim could set the stage for complicated negotiations on a swap with Israel, which is holding thousands of Palestinians in its prisons.

An unknown number of civilians were also taken. AP journalists saw four taken from the kibbutz of Kfar Azza, including two women. In Gaza, a black jeep pulled to a stop and, when the rear door opened, a young Israeli woman stumbled out, bleeding from the head and with her hands tied behind her back. A man waving a gun in the air grabbed her by the hair and pushed her into the vehicle’s back seat. Israeli TV reported that workers from Thailand and the Philippines were also among the captives.

In the kibbutz of Nahal Oz, just 4 kilometers (2.5 miles) from the Gaza Strip, terrified residents who were huddled indoors said they could hear constant gunfire echoing off the buildings as firefights continued.

“With rockets we somehow feel safer, knowing that we have the Iron Dome (missile defense system) and our safe rooms. But knowing that terrorists are walking around communities is a different kind of fear,” said Mirjam Reijnen, a 42-year-old volunteer firefighter and mother of three in Nahal Oz.

A major question now was whether Israel will launch a ground assault into Gaza, a densely populated enclave of more than 2 million people, a move that in the past has brought intensified casualties.

Israel’s military was bringing four divisions of troops as well as tanks to the Gaza border, joining 31 battalions already in the area, the spokesman Hagari said.

In Gaza, much of the population was thrown into darkness after nightfall, as electrical supplies from Israel – which supplies almost all the territories’ power – was cut off.

Hamas said it had planned for a potentially long fight. “We are prepared for all options, including all-out war,” the deputy head of the Hamas political bureau, Saleh al-Arouri, told Al-Jazeera TV. “We are ready to do whatever is necessary for the dignity and freedom of our people.”

U.S. President Joe Biden condemned “this appalling assault against Israel by Hamas terrorists from Gaza.” He spoke with Netanyahu and said Israel “has a right to defend itself and its people.” according to a White House statement.

Saudi Arabia, which has been in talks with the U.S. about normalizing relations with Israel, called on both sides to exercise restraint. The kingdom said it had repeatedly warned about the danger of “the situation exploding as a result of the continued occupation (and) the Palestinian people being deprived of their legitimate rights.”

Lebanon’s Hezbollah militant group congratulated Hamas, praising the attack as a response to “Israeli crimes.” The group said its command in Lebanon was in contact with Hamas about the operation.

The attack comes at a time of historic division within Israel over Netanyahu’s proposal to overhaul the judiciary. Mass protests over the plan have sent hundreds of thousands of Israeli demonstrators into the streets and prompted hundreds of military reservists to avoid volunteer duty - turmoil that has raised fears over the military’s battlefield readiness and raised concerns about its deterrence over its enemies.

It also comes at a time of mounting tensions between Israel and the Palestinians, with the peace process effectively dead for years. Over the past year Israel’s far-right government has ramped up settlement construction in the occupied West Bank, Israeli settler violence has displaced hundreds of Palestinians there, and tensions have flared around a flashpoint Jerusalem holy site.

Israel has maintained a blockade over Gaza since Hamas seized control of the territory in 2007. The bitter enemies have fought four wars since then.