DEIR AL-BALAH, Gaza Strip >> Israel launched airstrikes across the Gaza Strip early Tuesday, killing more than 400 Palestinians, local health officials said, and shattering a ceasefire in place since January with its deadliest bombardment in a 17-month war with Hamas.

Prime Minister Benjamin Netanyahu ordered the strikes, which killed mostly women and children, after Hamas refused Israeli demands to change the ceasefire agreement. In a statement aired on national television, he said the attack was “only the beginning” and that Israel would press ahead until it achieves all of its war aims — destroying Hamas and freeing all hostages held by the fighter group. All further ceasefire negotiations will take place “under fire,” he said. The White House said it had been consulted and voiced support for Israel’s actions.

The Israeli military ordered people to evacuate eastern Gaza and head toward the center of the territory, indicating that Israel could soon launch renewed ground operations. The new campaign comes as aid groups warn supplies are running out two weeks after Israel cut off all food, medicine, fuel and other goods to Gaza’s 2 million Palestinians.

“Israel will, from now on, act against Hamas with increasing military strength,” Netanyahu’s office said.

The attack during the Muslim holy month of Ramadan could signal the full resumption of a war that has already killed tens of thousands of Palestinians and caused widespread destruction across Gaza. It also raised concerns about the fate of the roughly two dozen hostages held by Hamas who are believed to still be alive. The renewal of the campaign against Hamas, which receives support from Iran, came as the U.S. and Israel stepped up attacks this week across the region. The U.S. launched deadly strikes against Iran-allied rebels in Yemen, while Israel has targeted Iran-backed fighters in Lebanon and Syria.

A senior Hamas official said Netanyahu’s decision to return to war amounts to a “death sentence” for the remaining hostages. Izzat al-Risheq accused Netanyahu of launching the strikes to save his far-right governing coalition.

Hamas said at least six senior officials were killed in Tuesday’s strikes. Israel said they included the head of Hamas’ civilian government, a justice ministry official and two security agency chiefs.

There were no reports of any attacks by Hamas several hours after the bombardment.

But Yemen’s Houthi rebels fired rockets toward Israel for the first time since the ceasefire began. The volley set off sirens in Israel’s southern Negev desert but was intercepted before it reached the country’s territory, the military said.

The strikes came as Netanyahu faces mounting domestic pressure, with mass protests planned over his handling of the hostage crisis and his decision to fire the head of Israel’s internal security agency. His latest testimony in a long-running corruption trial was canceled after the strikes.

The strikes appeared to give Netanyahu a political boost.

A far-right party led by Itamar Ben-Gvir that had bolted the government over the ceasefire announced Tuesday it was rejoining. The main group representing families of the hostages accused the government of backing out of the ceasefire.

“We are shocked, angry and terrified by the deliberate dismantling of the process to return our loved ones from the terrible captivity of Hamas,” the Hostages and Missing Families Forum said. Strikes across Gaza pounded homes, sparked fires in a tent camp outside the southern city of Khan Younis and hit at least one school-turned-shelter.

After two months of relative calm during the ceasefire, stunned Palestinians found themselves once again digging loved ones out of rubble and holding funeral prayers over the dead at hospital morgues.

“Nobody wants to fight,” Nidal Alzaanin, a resident of Gaza City, said. “Everyone is still suffering from the previous months.”