Hamas' unprecedented attack on Israel and the war it launched has raised new questions about the influence of its main sponsor, Iran, and whether it had anything to do with the assault.

From Tel Aviv to Washington, however, no one is willing to directly blame Iran as they say they lack direct evidence. Tensions between the Islamic Republic and the West remain high over its rapidly advancing nuclear program. In Tehran, even its supreme leader has denied the country being involved while praising what he described as the "capable, smart and courageous" militants who killed more than 1,000 Israelis and for the first time took over 100 civilians and soldiers as hostages.

Residents in Gaza are facing an imminent loss of electricity as fuel supplies run dangerously low in the sealed-off territory. Israeli airstrikes left entire neighborhoods demolished Wednesday, and hospitals in the Gaza Strip are struggling to treat the injured with dwindling medical supplies.

The war, which has claimed more than 2,200 lives on both sides, is expected to escalate. The weekend attack that Hamas said was retribution for worsening conditions for Palestinians under Israeli occupation has inflamed Israel's determination to crush the group's hold in Gaza.

Israel's military said it has responded with artillery fire from the Golan Heights after munitions were launched toward territory it has occupied since 1967.

"Soldiers are responding with artillery and mortar shells toward the origin of the launching in Syria," an Israeli military statement said, on the fourth day of a war with Gaza-based Hamas militants that has sent regional tensions soaring.

The death toll from five days of ferocious fighting between Hamas and Israel rose sharply overnight as Israel kept up its bombardment of Gaza Wednesday after recovering the dead from the last communities near the border where Palestinian militants had been holed up.

In Israel, the death toll from Saturday's shock cross-border assault by Hamas militants rose to 1,200, making it the deadliest attack in the country's 75-year history, while Gaza officials reported more than 900 people killed as Israel pounded the territory with air strikes.

In mosques, football stadiums and towns across the Arab world, pro-Palestinian sentiment has surged after a shock Hamas attack on Israel, sparking a groundswell of solidarity for the Palestinians.

From Ramallah to Beirut, Damascus, Baghdad and Cairo, people have distributed sweets, danced and chanted prayers in support of the "resistance" to Israel's long-standing occupation of Palestinian land.

Syria boycotted a hearing at the United Nations' top court on Tuesday where the Netherlands and Canada accused Damascus of a years-long campaign of "institutionalized" torture against its own people.

The hearing was focused on a preliminary Dutch and Canadian request for the court to impose orders — known as provisional measures — on Syria to halt torture immediately to protect potential victims while their case accusing Damascus of breaching the torture convention proceeds through the International Court of Justice.

French President Emmanuel Macron Tuesday denounced "unacceptable blackmail" by Hamas after the Palestinian militant group threatened to execute some of the around 150 hostages it abducted in a weekend assault.

"The blackmail by Hamas after its terrorist acts is odious and unacceptable," Macron told reporters on a visit to Germany.

Over 180,000 Palestinians in the Gaza Strip are packed into United Nations shelters as Israeli warplanes pound the tiny territory of 2.3 million people after their Hamas militant rulers launched an unprecedented weekend attack on Israel.

Among them is 27-year-old Sabreen al-Attar. She sprang into action when she heard rocket after rocket whoosh over her farmland in Beit Lahiya just north of the Israeli border on Saturday. She knew from experience that Israeli retaliation would be swift and severe.

The latest Israel-Palestinian war reverberated around the world Tuesday, as foreign governments tried to determine how many of their citizens were dead, missing or in need of medical help or flights home.

Numerous countries also offered to play a role in mediating an end to the fighting, which already has killed at least 1,600 people. The death toll was expected to grow as Israel pummeled the Gaza Strip with airstrikes and sent Palestinians fleeing into U.N. shelters.

Hezbollah should not make the "wrong decision" of opening a second front against Israel as it battles attacks by Hamas, a senior U.S. defense official warned Monday.

"We are deeply concerned about Hezbollah making the wrong decision and choosing to open a second front to this conflict," the official told journalists.