Israel and Hamas traded more heavy fire Thursday in the Gaza war that has killed thousands as U.S. Secretary of State Antony Blinken visited to stress strong solidarity but also urge restraint to protect Palestinian civilians.

Israel's army has hammered Hamas with thousands of strikes ahead of what is widely expected to be a ground invasion of the crowded territory, after Hamas gunmen killed 1,200 Israelis, mostly civilians, and took about 150 hostages.

Israeli Energy Minister Israel Katz vowed Thursday his country would not allow basic resources or humanitarian aid into Gaza until Hamas released the people it abducted during its surprise weekend onslaught.

"Humanitarian aid to Gaza? No electric switch will be turned on, no water tap will be opened and no fuel truck will enter until the Israeli abductees are returned home," he said in a statement.

Palestinians in Gaza lined up outside bakeries on Thursday after spending the night in pitch darkness surrounded by the ruins of pulverized neighborhoods, as Israel launched new airstrikes and said it was preparing for a possible ground invasion.

International aid groups warned that deaths in Gaza could accelerate as Israel prevents delivery of supplies. The war, which was ignited by a bloody and wide-ranging Hamas attack into Israel, has already claimed at least 2,400 lives on both sides.

Saudi Arabia's de facto ruler and Iran's president spoke by phone about the war between Israel and Hamas, Saudi state media said early Thursday, their first call since a surprise rapprochement in March.

Saudi Crown Prince Mohammed bin Salman received a call on Wednesday from the Iranian leader, Ebrahim Raisi, during which they discussed "the current military situation in Gaza and its environs", the official Saudi Press Agency (SPA) said.

A top opposition Israeli politician said Wednesday that he has reached an agreement to enter a wartime unity government with Prime Minister Benjamin Netanyahu.

Benny Gantz, a former defense minister and military chief of staff, released what he said was a joint statement with Netanyahu.

A potential intervention by Hezbollah and uncertainty over the role played by Iran itself are risk factors that could push the unprecedented conflict between Israel and Hamas into a wider regional war, analysts say.

For now, there is no indication of an impending offensive by Hezbollah against Israel, despite growing border tensions.

Turkey's president on Wednesday vowed to intensify strikes against Kurdish fighters in Syria and Iraq.

"We have already intensified air operations and we will continue, and show the terrorists that we can destroy them anywhere and at any moment," Recep Tayyip Erdogan said, referring to fighters of the Kurdistan Workers' Party (PKK) -- listed as a terror group by Ankara and its Western allies.

At the most harrowing of times, some Israeli citizens living overseas aren't running from the war at home, but to it. From Athens to New York, they're rushing to airports and diving into online chat groups for help, desperate to make their way to the country after Hamas militants attacked.

Some of these Israelis abroad are yearning to serve, whether that means fighting in a military reserve unit or volunteering to shuttle supplies to those in need, even as the war has already claimed at least 1,800 lives and shows no signs of abating. On Tuesday, Israel's military expanded its mobilization of reservists to 360,000, according to the country's media, as it ramped up its retaliation for the surprise attacks.

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.