AMNA NAWAZ: Welcome to the "NewsHour."

After a week-long cease-fire, in which Hamas released more than a hundred Israeli and foreign hostages, Israel freed more than 240 Palestinians, and hundreds of aid trucks were allowed into Gaza, war has returned to the region.

Negotiators are working to reinstate the temporary truce that ended this morning, but the health authority in Gaza, which is controlled by Hamas, said more than 175 Palestinians have already been killed.

Nick Schifrin begins our coverage.

NICK SCHIFRIN: Tonight, Israeli flares light up the Gaza sky, and Israel's Iron Dome above Tel Aviv intercepts rockets fired from Gaza.

As war has re-erupted, Israel vows to continue its military mission.

BENNY GANTZ, Israeli War Cabinet Minister (through translator): The state of Israel is committed to winning the campaign, and this victory includes both a supreme effort to return the abductees and also the removal of the threat of Hamas.

NICK SCHIFRIN: Israel and the U.S. said Hamas failed to produce another list of hostages to be released today and, before the cease-fire expired, began firing rockets from Gaza into Israel.

By the end of the day, Israel said Hamas had fired more than 50 rockets into Israel.

Israel immediately resumed it's air campaign.

In the Al-Maghazi refugee camp in the center of Gaza, crowds of men lifted the dead out of what Gazans say used to be an apartment complex.

Residents told us at least 15 were killed in their sleep.

ABU ZIYAD, Al-Maghazi Refugee Camp Resident (through translator): There was no warning at 7:00 a.m.

It happened right after the so-called truce ended.

It was full of innocent children and normal civilians.

NICK SCHIFRIN: In Southern Gaza, residents walked through the rubble from an Israeli airstrike on what they said was another apartment building.

Mahmoud Siyam spoke to us as Israeli drones arrived above.

MAHMOUD SIYAM, Palestinian Politician: They thought this is a safer place to stay here.

And, this morning, Israel attack without warning.

We ask the international law, international -- all over the world to stop this war.

NICK SCHIFRIN: Thousands of Palestinians fled their homes near the border with Israel along the main road leading to Khan Yunis.

But, today, Khan Yunis itself was filled with smoke and grief.

Wounded children arrived into a hospital.

Even Gaza's most vulnerable were not spared the horrors of war.

LAMA ABU MOUS, Wounded Palestinian (through translator): I found my mother and my younger brother.

I don't know where my older brother is.

NICK SCHIFRIN: The U.S. has pressed Israel to reduce civilian casualties.

And, today, Israel used new leaflets, declaring Khan Yunis a combat zone and urging Gazans to move south to Rafah.

But even in Rafah today, this was the aftermath of what residents said was an Israeli airstrike.

ANTONY BLINKEN, U.S. Secretary of State: We saw Israel take steps immediately today to start to get information to people about where safe areas are, how they can get out of harm's way.

NICK SCHIFRIN: During his third trip to the region since the October 7 attacks, including a quick stop today at the COP climate conference in Dubai, Secretary of State Antony Blinken said Israel bears a special burden to avoid civilian casualties.

ANTONY BLINKEN: I made clear that, after the pause, it was imperative that Israel put in place clear protections for civilians and for sustaining humanitarian assistance going forward.

NICK SCHIFRIN: For hours today, Israel blocked humanitarian trucks currently sitting in Egypt from entering Gaza.

But, tonight, U.S. officials said, at their urging, trucks would soon reenter Gaza.

What the U.S. is also hoping resumes, the release of more Israeli hostages.

So far, more than 100 have been freed, but Hamas still hasn't provided another list today, and claims it doesn't hold any more women and children, even though 10 to 20 are still believed to be held hostage.

U.S. and Israeli officials don't believe Hamas ' claim.

Israeli officials said half-a-dozen Israelis who disappeared on October the 7th, including Ofir Tzarfati, have been confirmed dead.

Hamas today blamed Israel for the war resuming, but said it would continue indirect talks, mediated by Qatar.

OSAMA HAMDAN, Hamas Spokesperson (through translator): We believe that the Qatari side will continue its communications, and we will be ready to engage with them if the Israelis respond and cease the aggression.

NICK SCHIFRIN: Demonstrators in Tel Aviv urged the Israeli government to prioritize hostage releases.

But Qatar warned that they are less likely now that war has resumed.

For the "PBS NewsHour," I'm Nick Schifrin.