Israeli warplanes hammered the Gaza Strip neighbourhood by neighbourhood on Tuesday, reducing buildings to rubble and sending people scrambling to find safety in the tiny, sealed-off territory as Israel vowed a retaliation for Hamas’ surprise weekend attack that would “reverberate...For generations”.

Aid organisations pleaded for the creation of humanitarian corridors to get aid into Gaza, warning that hospitals overwhelmed with wounded were running out of supplies. Israel has stopped all access of food, fuel and medicines into Gaza, and the sole remaining access from Egypt shut down on Tuesday after air strikes hit near the border crossing.

The war began after Hamas militants stormed into Israel on Saturday, bringing gunbattles to its streets for the first time in decades. At least 1,600 lives have already been claimed on both sides, and perhaps hundreds more. Hamas and other militant groups in Gaza hold more than 150 soldiers and civilians hostage, according to Israel.

The conflict is only expected to escalate. Israel expanded the mobilisation of reservists to 360,000 on Tuesday, according to the country’s media. After days of fighting, Israel’s military said on Tuesday morning that it had regained effective control over areas Hamas attacked in its south, and of the Gaza border.

A looming question is whether Israel will launch a ground offensive into Gaza — a 40 km long strip of land wedged among Israel, Egypt and the Mediterranean Sea that is home to 2.3 million people and has been governed by Hamas since 2007.

 The Israeli military said it struck hundreds of targets overnight in Gaza City’s Rimal neighbourhood, an upscale district that is home to ministries of the Hamas-run government, as well as universities, media organisations and the offices of aid organisations.

Palestinian Civil Defence forces pulled Abdullah Musleh out of his basement together with 30 others after their apartment building was flattened by the air strikes.

“I sell toys, not missiles,” the 46-year-old said, weeping. “I want to leave Gaza. Why do I have to stay here? I lost my home and my job.”

After hours of nonstop attacks, residents left their homes at daybreak to find buildings torn in half by air strikes or reduced to mounds of concrete and rebar. Cars were flattened and trees burned out on residential streets that had been transformed into moonscapes.

The devastation signalled what appeared to be a new Israeli tactic: warning civilians to leave certain areas and then hitting those areas with unprecedented intensity. On Tuesday afternoon, the military warned residents of another nearby neighbourhood to evacuate and move into the centre of Gaza City.

“There is no safe place in Gaza right now, you see decent people being killed every day,” Hasan Jabar, a Gaza journalist, said after three other Palestinian journalists were killed in the Rimal bombardment. “I am genuinely afraid for my life.”

The bombardments and Israel’s threats to topple Hamas sharpened questions about the group’s strategy and objectives. But it is unclear what options it has in the face of the ferocity of Israel’s retaliation and the potential of losing much of its government infrastructure.

Hours after Saturday’s incursion began, a senior Hamas official Saleh al-Arouri said the group had planned for all possibilities, including “all-out war,” and was ready to suffer “severe blows”.

Desperation has grown among Palestinians, many of whom see nothing to lose under unending Israeli control and increasing settlements in the West Bank, the blockade in Gaza and what they see as the world’s apathy.

Al-Arouri’s comments suggested Hamas expected the fight to spread to the West Bank and possibly for Lebanon’s Hezbollah to open a front in the north. But despite some eruptions of violence, neither has happened on a significant scale, especially amid a heavy Israeli lockdown on West Bank Palestinians.

In hopes of blunting the bombardment, Hamas has threatened to kill one Israeli civilian captive any time Israel targets civilians in their homes in Gaza “without prior warning”. Israel’s foreign minister, Eli Cohen, warned in response that “this war crime” would not be forgiven.

Israel, in turn, appears determined to crush Hamas no matter the cost.

The militants’ attack stunned Israel with a death toll unseen since the 1973 war with Egypt and Syria, and those deaths happened over a longer period of time. It brought horrific scenes of Hamas militant gunning down civilians in their cars on the road, in streets of towns, and at a music festival attended by thousands in the desert near Gaza, while dragging men, women and children into captivity.

The Israeli military said more than 900 people have been killed in Israel.

The bodies of roughly 1,500 Hamas militants were found on Israeli territory, the military said.