Israel, reeling from the deadliest attack on its territory in half a century, formally declared war on Hamas on Sunday as the conflict’s death toll surged to 1,000 after the Palestinian militant group launched a massive surprise assault from Gaza.

AFP reports that Prime Minister Benjamin Netanyahu steeled the shocked and grieving nation for a “long and difficult” war ahead after Hamas launched a barrage of rockets at Israel before dawn on Saturday and sent in fighters who gunned down civilians and took at least 100 hostages.

Several Germans, who are also Israeli nationals, were among those kidnapped by militants of the Palestinian Hamas group during its raids into Israel, German ministerial sources said on Sunday.

The sources did not specify the numbers involved.

United States President Joe Biden has, however, ordered “additional support” for Israel after the attack, the White House said Sunday, without giving details.

“The President directed additional support for Israel in the face of this unprecedented terrorist assault by Hamas,” the White House said in a statement.

In Gaza, which was hammered by Israeli air strikes on 800 targets ahead of what many feared may be a looming ground invasion, officials reported at least 370 deaths, with thousands more wounded across the war zone.

Tens of thousands of Israeli forces were deployed to battle holdout Hamas fighters in the South, where the bodies of civilians had been found strewn on roads and in town centres.

“The enemy is still on the ground,” military spokesman Daniel Hagari told journalists as a second night fell after the attack, adding Israel was reinforcing its military strength near the Gaza Strip.

Gun battles raged as the Israeli army sought to secure desert regions near the coastal enclave, rescue Israeli hostages and evacuate all areas near Gaza.

“We’ll reach each and every community until we kill every terrorist in Israel,” vowed Hagari, a day after hundreds of Hamas fighters launched their shock offensive and surged into Israel using vehicles, boats and even motorised paragliders.

There was widespread shock and dismay in Israel after about 100 citizens were captured by Hamas and abducted into Gaza, with images circulating on social media of bloodied hostages, and distraught relatives pleading for the state to rescue them.