International mediators were pressing to extend a cease-fire in Gaza that has halted the deadliest Israeli-Palestinian violence in decades but is set to expire after Monday, as Israel and Hamas prepared for a fourth exchange of militant-held hostages for Palestinians imprisoned by Israel.

Israel has said it would extend the cease-fire by one day for every 10 additional hostages released. Hamas has also said it hopes to extend the four-day truce, which came into effect Friday after several weeks of indirect negotiations mediated by the United States, Qatar and Egypt.

The tense cease-fire between Israel and Hamas appeared to be back on track early Sunday after the release of a second group of militant-held hostages and Palestinians from Israeli prisons, but the swap followed an hourslong delay that underscored the truce's fragility.

The exchange was delayed Saturday evening after Hamas accused Israel of violating the agreement, which has brought the first significant pause in seven weeks of war marked by the deadliest Israeli-Palestinian violence in decades, vast destruction and displacement across the Gaza Strip, and a hostage crisis that has shaken Israel.

Israeli forces operating in the occupied West Bank killed at least eight Palestinians in a 24-hour period, Palestinian health officials said Sunday, as a fragile pause in fighting between Israel and Hamas in the Gaza Strip entered its third day.

Violence in the West Bank has surged in the weeks since Hamas attacked Israel on Oct. 7, setting off a devastating war in the Gaza Strip. Israeli forces have killed dozens of Palestinians and arrested hundreds in the West Bank. Jewish West Bank settlers have also stepped up attacks.

Hamas' military wing on Sunday confirmed the commander of its northern brigade, Ahmed Al-Ghandour, and three other senior leaders had been killed during Israel's offensive against the Palestinian movement.

In a statement, the Ezzedine Al-Qassam Brigades said Ghandour was a member of its military council and named three other leaders who had died, including Ayman Siyyam, who Israeli media reports said was head of the Brigades' rocket-firing units.

Over three dozen Palestinian prisoners returned home to a hero's welcome in the occupied West Bank on Friday following their release from Israeli prisons as part of a cease-fire deal between Israel and Hamas.

The procession of freed prisoners, some accused of minor offenses and others convicted in attacks, at a checkpoint outside of Jerusalem stoked massive crowds of Palestinians into a chanting, clapping, hand-waving, screaming frenzy.

Hamas was expected to swap more of its hostages Saturday for prisoners held by Israel on the second day of a cease-fire that has allowed critical humanitarian aid into the Gaza Strip and given civilians their first respite after seven weeks of war.

A container ship owned by an Israeli billionaire came under attack by a suspected Iranian drone in the Indian Ocean as Israel wages war on Hamas in the Gaza Strip, an American defense official said Saturday.

The attack Friday on the CMA CGM Symi comes as global shipping increasingly finds itself targeted in the weekslong war that threatens to become a wider regional conflict — even as a truce has halted fighting and Hamas exchanges hostages for Palestinian prisoners held by Israel.

U.S. President Joe Biden said Friday's release of a first group of hostages taken by Hamas was just a "start" and that there were "real" chances to extend a temporary truce in Gaza.

Speaking to reporters in Nantucket, Massachusetts, where he was spending the Thanksgiving holiday with his family, Biden also said it was time to "renew" work on creating two-state solution for peace between Israel and the Palestinians.

Hamas on Friday freed a first batch of hostages seized in the deadliest attack in Israel's history under a deal that saw a temporary truce take hold in war-ravaged Gaza. Israel meanwhile release 39 Palestinian women and children from its prisons.

Thirteen Israeli hostages captured during Palestinian militants' cross-border raids were back in Israeli territory where they would undergo medical checks before being reunited with their families, the army said.

Israel's military offensive has turned much of northern Gaza into an uninhabitable moonscape. Whole neighborhoods have been erased. Homes, schools and hospitals have been blasted by airstrikes and scorched by tank fire. Some buildings are still standing, but most are battered shells.

Nearly 1 million Palestinians have fled the north, including its urban center, Gaza City, as ground combat intensified. When the war ends, any relief will quickly be overshadowed by dread as displaced families come to terms with the scale of the calamity and what it means for their future.