Dozens were killed in Israeli strikes across the Gaza Strip on Thursday, the territory’s health ministry said, as U.S.-backed attempts to push Israel and Hamas to agree to a new cease-fire remain deadlocked.

Dozens more were injured in the attacks, according to the ministry, which does not distinguish between civilians and combatants.

Israel has threatened a significant military escalation in the coming days unless Hamas lays down its arms and frees the remaining hostages it holds. But the Palestinian armed group has rejected Israel’s conditions, demanding an end to the war and a full Israeli withdrawal in exchange for releasing the captives.

The Trump administration is seeking to broker an end to the war, which began after the Hamas-led attack on Israel on Oct. 7, 2023, in which about 1,200 people were killed and about 250 people taken to Gaza as hostages.

Israel’s subsequent military campaign against Hamas has killed more than 50,000 people, including thousands of children, according to Gaza health officials. Gaza’s health ministry said that more than 50 people had been killed in the latest strikes. Despite its immense toll, the war has failed to either decisively subdue Hamas or free all of the hostages.

Over the weekend, the United States and Hamas reached a separate agreement to free Edan Alexander, the last American hostage left alive in Gaza, effectively bypassing Israel. President Trump wrote on social media that he hoped it would be the “first of those final steps necessary to end this brutal conflict.”

Israeli negotiators traveled to Qatar this week for the latest round of indirect cease-fire talks with Hamas to free the remaining hostages. The following day, the office of Benjamin Netanyahu, the Israeli prime minister, said he had spoken with Steve Witkoff, Mr. Trump’s Middle East envoy, as well as the Israeli negotiating team.

The Israeli military campaign, however, has not stopped. On Tuesday, Israeli aircraft bombarded the area around the European Hospital in the southern city of Khan Younis in an attempt to kill Muhammad Sinwar, one of Hamas’s top leaders in Gaza. Mr. Sinwar’s older brother, Yahya Sinwar, masterminded the Oct. 7 attacks and led Hamas before he was killed by Israeli forces last year.

Neither Israel nor Hamas has publicly commented on the fate of the younger Mr. Sinwar.