ALSO SEE: Israeli Airstrike Hits Marketplace in Gazan Refugee Camp, Killing Dozens

Sixty people died in a strike in the Jabalia refugee camp, a rescue worker said. There was no immediate confirmation from the Gazan Health Ministry.

An Israeli airstrike ripped through a crowded marketplace in northern Gaza on Monday afternoon, killing dozens of people, according to a rescue worker and witnesses.

The strike transformed a central shopping and transportation district in northern Gaza’s Jabalia refugee camp into a scene of unrecognizable devastation. Videos shared on social media and distributed by Palestinian news agencies show bodies strewn amid the detritus of what moments earlier had been a busy market selling produce and other goods.

Broken concrete and twisted metal from the surrounding buildings filled the square, where people rushed through the rubble and clouds of smoke searching for survivors. As a fire burned on the edge of the square, a policeman, bloodied and covered in dust, sat off to its side.

“Is he dead? Is he dead?” a man was heard yelling in one video.

The strike came as part of Israel’s response to Saturday’s attack, when hundreds of Palestinian fighters swept across Israel’s border with the Gaza Strip, killing civilians and soldiers in shooting sprees, and firing thousands of rockets toward the center of the country. The fighters say they are holding 150 hostages, civilians and soldiers. More than 700 people have been killed in Israel and nearly 2,400 injured.

Amid widespread fear in Gaza about the Israeli response, many people fleeing other parts of the blockaded enclave had come to seek shelter in central Jabalia, where shops and homes surround the market area. Monday’s strike hit as vendors and customers packed the marketplace, stocking up on food and produce.

Sixty people died in the strike, according to a paramedic with the Red Crescent who requested anonymity because they were not authorized to speak to the press. There was no immediate confirmation from the Gazan Health Ministry.

Israeli airstrikes began pounding the Gaza Strip on Saturday. Since then, at least 560 Palestinians have been killed, the Gazan Health Ministry said on Monday, and nearly 3,000 others wounded. The casualties included 78 children and 41 women, the ministry said, in some cases entire families. It was not clear how many of the other casualties were fighters, whether involved in the attack on Israel, or from the Israeli airstrikes.

“The Israelis have lost their minds,” said Raji Sourani, a lawyer with the Palestinian Centre for Human Rights in Gaza, adding: “They are annihilating entire families.”

Israel says its strikes are targeting centers of operations of Hamas, the armed group that controls Gaza. It has confirmed hitting several mosques, saying it was targeting Hamas infrastructure or militants inside the buildings. The United Nations and Palestinian officials have said that at least two hospitals and multiple homes also have been hit, and many Gazans say they have nowhere to go to escape the onslaught of Israeli strikes.

Israel’s defense minister on Monday announced a “complete siege” of Gaza, saying “no electricity, no food, no water, no fuel” would be allowed in. The enclave has already been under a suffocating 16-year blockade by Israel and Egypt, which limits what comes into Gaza and prevents most people from leaving.

Strikes hit four mosques in the Shati refugee camp on Monday, toppling their domes in attacks that the Gazan authorities said had killed people worshiping inside. Witnesses said boys had been playing soccer outside the mosque when the strike hit.

On Monday afternoon, neighbors were combing the rubble of the mosque, which was nearly unrecognizable as a place of worship.

Sumaya Ghabin, 30, was shaken awake at around 6 a.m. by the boom of an Israeli strike hitting the Gharbia Mosque, which is about two blocks away from her home and also near the Sousi Mosque.

“We woke up and find the house all dust and shrapnel,” she said. The windows had been blown out, she added, and her 10-year-old daughter was hiding under the covers screaming.