Israeli fighter jets hit Hamas targets in the Gaza Strip on Friday shortly after a weeklong truce expired, the military said, as the war resumed in full force.

Airstrikes hit southern Gaza, including the community of Abassan east of the town of Khan Younis, the Interior Ministry in the Hamas-run territory said. Another strike hit a home northwest of Gaza City.

Loud, continuous explosions were heard coming from the Gaza Strip and black smoke billowed from the territory.

Also read: More Israeli hostages freed and more Palestinian prisoners released under tenuous Gaza truce

In Israel, sirens blared at three communal farms near Gaza warning of incoming rocket fire, suggesting Hamas had also resumed its attacks.

The Israeli military's announcement of the strikes came only 30 minutes after the cease-fire expired at 7 a.m. (0500 GMT) Friday.

Earlier Friday, Israel accused Hamas of having violated the terms of the cease-fire, including by firing rockets toward Israel from Gaza.

The halt in fighting began Nov. 24. It initially lasted for four days, and then was extended for several days with the help of Qatar and fellow mediator Egypt.

During the week-long truce, Hamas and other militants in Gaza released more than 100 hostages, most of them Israelis, in return for 240 Palestinians freed from prisons in Israel.

Virtually all of those freed were women and children, but the fact that few such hostages remained in Gaza complicated reaching a deal for a further extension.

Also read: Truce in Gaza extended at last minute as talks over remaining Hamas captives get tougher

Hamas, a militant group that has ruled Gaza for 16 years, had also been expected to set a higher price for the remaining hostages, especially Israeli soldiers. About 140 hostages remain in Gaza, with more than 100 having been freed as part of the truce.

Qatar and Egypt, which have played a key role as mediators had sought to prolong the truce by another two days.

Israel has been under growing pressure from its main ally, the United States, to do more to protect Palestinian civilians when it resumes its strikes against Hamas.

U.S. Secretary of State Antony Blinken met Thursday with Israeli Prime Minister Benjamin Netanyahu and other top officials on his third visit to the region since the start of the war two months ago.

While expressing hope at the time that the cease-fire could be extended, Blinken said that if Israel resumed the war and moved against southern Gaza to pursue Hamas, it must do so in "compliance with international humanitarian law" and must have "a clear plan in place" to protect civilians. He said Israeli leaders understood that "the massive levels of civilian life and displacement scale we saw in the north must not be repeated in the south."

Also read: With deadline looming, diplomats seek to extend Gaza truce; more hostages, prisoners are freed

Israel had said it would maintain the truce until Hamas stops releasing captives, and vowed then to resume its campaign to crush Hamas, even as the Biden administration has urged it to operate with far greater precision if it does so.

Most of Gaza's population is now crammed into the south with no exit, raising questions over how an Israeli offensive there can avoid heavy civilian casualties.

Netanyahu had been under intense pressure from families of the hostages to bring them home. But his far-right governing partners were also pushing him to continue the war until Hamas is destroyed, and could abandon his coalition if he is seen as making too many concessions.

A total of 83 Israelis, including dual nationals, were freed during the truce, most of whom appeared physically well but shaken. Another 24 hostages — 23 Thais and one Filipino — were also released, including several men.

It's not clear how many of the remaining women hostages are soldiers.

Israel has said around 125 men are still held hostage.

Before the cease-fire, Hamas released four hostages, and the Israeli army rescued one. Two others were found dead in Gaza.

The 240 Palestinians released so far under the cease-fire were mostly teenagers accused of throwing stones and firebombs during confrontations with Israeli forces. Several of the freed women were convicted by military courts of attempting to attack soldiers, some of them after being found carrying scissors or knives near security positions.

Hamas started the war with a deadly Oct. 7 attack on Israel, during which it and other Palestinian militants killed about 1,200 people, mostly civilians, and took around 240 people captive. Authorities have only provided approximate figures.

Since then, Israel's bombardment and invasion in Gaza have killed more than 13,300 Palestinians, roughly two-thirds of them women and minors, according to the Health Ministry in Hamas-ruled Gaza, which does not differentiate between civilians and combatants. More than three-quarters of the population of 2.3 million have been uprooted, after weeks of Israeli bombardment and a ground campaign, leading to a humanitarian crisis.

The toll is likely much higher, as officials have only sporadically updated the count since Nov. 11. The ministry says thousands more people are feared dead under the rubble.

Israel says 77 of its soldiers have been killed in the ground offensive. It claims to have killed thousands of militants, without providing evidence.

Palestinians in Gaza have called for a permanent end to the war, saying the temporary truces don't resolve the humanitarian catastrophe in the territory. Over 1.8 million people have fled their homes, with more than 1 million sheltering in U.N. schools and struggling to find basic items including cooking gas and flour.