JERUSALEM -- The war between Israel and the militant group Hamas raged for a fifth day on Wednesday, as Israeli warplanes hammered neighbourhood after neighbourhood in the Gaza Strip, reducing buildings to rubble and sending people scrambling to find safety.

As authorities in Gaza warned that rescue teams were unable to reach many areas and that electricity supplies would run out within hours, humanitarian groups pleaded for the creation of corridors that would allow them to deliver aid.

The war, which has claimed at least 2,200 lives on both sides, is expected to escalate.

Israel has vowed an unprecedented offensive against Hamas, after the Islamic militant group's fighters broke through the border fence Saturday and stormed into the country's south.

The Israeli military said more than 1,200 people, including 155 soldiers, have died in Israel since then. In Gaza, 1,055 people have been killed, including 260 children and 230 women, according to authorities there. Israel says hundreds of Hamas fighters are among them. Thousands have been wounded on both sides.

More than 150 people have also been kidnapped by Hamas and other militant groups. The armed wing of Hamas has warned it will kill a hostage every time Israel's military bombs civilian targets without warning.

Here are some key takeaways from the war:

WHAT IS THE SITUATION IN GAZA?

Conditions in the coastal enclave, a crowded, 40-kilometre (25-mile) long strip of land that is home to 2.3 million people, were deteriorating quickly Wednesday as entire city blocks were reduced to rubble and residents searched for places to go.

Gaza's Civil Defence Department warned that there were too few rescue teams to search for survivors buried under rubble, and that teams were unable to reach many places because of damage to roads and constant bombardments.

"There is no safe place in Gaza right now," said journalist Hasan Jabar after three Palestinian journalists were killed in the bombardment of a downtown neighbourhood home to government ministries, media offices and hotels. "I am genuinely afraid for my life."

More than 250,000 people in Gaza have fled their homes, the UN said. Most of them have crowded into schools run by the UN agency for Palestinian refugees. Most of the territory's residents are unable to leave due to a years-long blockade maintained by Israel and Egypt.

Israel has cut off supplies of food, fuel, electricity and medicine into Gaza, and the sole remaining access from Egypt was shut down Tuesday after airstrikes hit near the border crossing. Gaza's power authority says its sole power plant will run out of fuel within hours, leaving the territory without electricity.

WILL ISRAEL LAUNCH A GROUND ASSAULT?

Israel is taking a new approach to its air war, warning civilians to evacuate neighbourhood after neighbourhood, and then inflicting devastation. It's also mobilized some 360,000 reservists.

The new tactics could point to a new objective. Four previous rounds of Israel-Hamas fighting between 2008 and 2021 all ended inconclusively, with Hamas battered but still in control.

This time, Israel's government is under intense pressure from the public to topple Hamas, a goal considered unachievable in the past because it would require a reoccupation of the Gaza Strip, at least temporarily.

"We will not allow a reality in which Israeli children are murdered," Israeli Defence Minister Yoav Gallant said in a meeting with soldiers near the southern border on Tuesday. "I have removed every restriction -- we will eliminate anyone who fights us, and use every measure at our disposal."

WHAT HAS BEEN THE RESPONSE FROM THE U.S. AND OTHER NATIONS?

U.S. President Joe Biden on Tuesday again condemned the attack by Hamas, calling it an act of "pure unadulterated evil."

Biden warned adversaries not to take advantage of the crisis. "I have one word: Don't. Don't."

U.S. Secretary of State Antony Blinken is traveling to Israel on an urgent mission to show support for Israel, the State Department said Tuesday.

The Ford carrier strike group has arrived in the far Eastern Mediterranean, within range to provide a host of air support or long-range strike options for Israel if requested, but also to boost the U.S. military presence to prevent the now 4-day-old war with Hamas from spilling over into a more dangerous regional conflict, a U.S. official told The Associated Press on Tuesday.

The official spoke on the condition of anonymity to discuss the arrival ahead of an official announcement.

Turkish President Recep Tayyip Erdogan has criticized Israel's blockade of Gaza, saying cutting off electricity and water is against the Palestinians' human rights.

Speaking at a joint news conference with Austrian Chancellor Karl Nehammer on Tuesday, Erdogan criticized U.S. plans to send an aircraft carrier to the region, saying the deployment could lead to "massacres."

President Abdel Fattah el-Sissi of Egypt, whose government maintains ties with Israel and Hamas, on Tuesday called for a ceasefire in the war.

WHAT ARE SOME OF THE WAR'S RIPPLE EFFECTS?

The war threatened to delay or derail a country-by-country diplomatic push by the United States to improve relations between Israel and its Arab neighbours.

The so-called normalization push, which began under former President Donald Trump's administration and was branded the Abraham Accords, is an ambitious effort to reshape the region and boost Israel's standing in historic ways. But critics have warned that it skips past Palestinian demands for statehood.

U.S. Secretary of State Antony Blinken said the Hamas attacks may have been driven in part by a desire to scuttle the United States' most ambitious part of the initiative: the sealing of diplomatic relations between rivals Israel and Saudi Arabia.

The Middle East's two greatest powers share a common enemy in Iran, a generous military and financial sponsor of Hamas.

WHAT IS THE STATUS OF FOREIGN CITIZENS IN ISRAEL?

Foreign governments tried to determine how many of their citizens were dead, missing or in need of medical help as many countries arranged evacuation flights.

U.S. President Joe Biden has confirmed that 14 U.S. citizens have been killed and that Americans are among the hostages captured by Hamas. White House National Security Adviser Jake Sullivan said Tuesday that at least 20 U.S. citizens are unaccounted for.

Russia has reported the deaths of four citizens, while France said at least eight were killed and the Philippines said two Filipinos were dead.

Twenty Thais were feared dead based on reports from employers, Thai Foreign Ministry spokesperson Kanchana Patarachoke said Tuesday, while 14 were believed to have been kidnapped.

The Austrian government said three Austrian-Israeli dual citizens may be among the people kidnapped by Hamas during its attack on Israel. Italy's foreign minister said an Italian-Israeli couple living on the Be'eri Kibbutz had been missing since the incursion and were "probably taken hostage."

WHAT PROMPTED HAMAS' ATTACK ON ISRAEL?

Hamas, which seeks Israel's destruction, says it is defending Palestinians' right to freedom and self-determination.

But the devastation following Hamas' surprise attack on Saturday has sharpened questions about its strategy and objectives. Hamas officials have said they planned for all possibilities, including a punishing Israeli escalation.

Desperation has grown among Palestinians, many of whom see nothing to lose under unending Israeli control and increasing settlements in the West Bank, a 16-year-long blockade in Gaza and what they see as the world's apathy.

In addition to citing long-simmering tensions, Hamas officials cite a long-running dispute over the sensitive Al-Aqsa Mosque that is sacred to both Muslims and Jews. Competing claims over the site, known to Jews as the Temple Mount, have spilled into violence before, including a bloody 11-day war between Israel and Hamas in 2021.

Tensions between Israel and the Palestinians escalated with recent violent Palestinian protests. In negotiations with Qatar, Egypt and the United Nations, Hamas has pushed for Israeli concessions that could loosen the blockade on the Gaza Strip and help halt a worsening financial crisis.