Fighting continued between Israeli forces and Hamas for the second day after Hamas infiltrated Israel-occupied territories by land, air and sea, killing around 659 Israelis and taking dozens hostage, Al Jazeera reported.

In retaliation, Israel launched airstrikes on Gaza resulting in the killing of at least 313 people and wounding over 2,000 on Sunday, the health ministry in the Palestinian enclave said.

The Israeli attacks flattened residential buildings in giant explosions, including a 14-storey tower, that held dozens of apartments in central Gaza city.

In southern Israel, Hamas gunmen were still fighting Israeli security forces 24 hours after a surprise, multi-pronged assault to send hundreds of fighters into nearby towns.

The battle between the Israeli forces and Hamas started following a barrage of more than 2,000 rockets fired from the Gaza Strip on Saturday. Air raid sirens wailed across southern and central Israel, and the army urged people to stay near bomb shelters.

The Palestinian militant group Hamas launched its most significant attack on Israel in years, infiltrating regions in the south of the country, according to local media and medical professionals.

“We decided to put an end to all the crimes of the occupation (Israel). Their time for rampaging without being held accountable is over,” the Ezzedine al-Qassam Brigades said.

“We announce Operation Al-Aqsa Flood and we fired, in the first strike of 20 minutes, more than 5,000 rockets.”

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As the battle raged for the second day, the Israeli army said that its troops were fighting Hamas militants at 22 locations after Hamas launched a surprise dawn attack a day earlier.

“There are still 22 locations where we are engaging with terrorists that came into Israel from the sea, from the land and from the air,” army spokesman Richard Hecht told journalists, adding the Hamas attack included a “robust ground invasion”.

Al Jazeera reported the killing of 600 Israelis in the ongoing battle as the Israeli military failed to repulse Hamas fighters from some of the towns and villages in Southern Israel.

Israeli broadcaster Reshet 13 TV News on Saturday said militants were holding Israelis hostage in the town of Ofakim, and that five Palestinian militants had been killed in the town of Sderot and homes had been set on fire.

Meanwhile, Israeli Prime Minister Benjamin Netanyahu said ‘We are in a state of war and we will win it’.

In a video statement Netanyahu said, “Citizens of Israel, we are at war. Not an operation, not an escalation — at war.”

Countries across the world called for restraint while the US condemned the attacks and said it was standing with Israel.

Amid the attack by Hamas that surprised the military, Israeli defence chiefs faced growing questions over how the disaster could have happened.

An army spokesman said there would be discussions on the intelligence preparation “down the road” but for the moment the focus was on fighting. “We’ll talk about that when we need to talk about it,” he told a briefing with reporters.

With input from agencies…