Israel and Hamas agreed to a deal to halt fighting in Gaza and exchange Israeli hostages for Palestinian prisoners, an official briefed on the deal told Reuters on Wednesday, opening the way to a possible end to a 15-month war that has upended the Middle East.

The agreement follows months of on-off negotiations brokered by Egyptian and Qatari mediators, with the backing of the United States, and came just ahead of the Jan. 20 inauguration of U.S. President-elect Donald Trump.

Israeli troops invaded Gaza after Hamas-led gunmen broke through security barriers and burst into Israeli communities on Oct. 7, 2023, killing 1,200 soldiers and civilians and abducting more than 250 foreign and Israeli hostages.

Israel’s campaign in Gaza has killed more than 46,000 people, according to Gaza health ministry figures, and left the narrow coastal enclave a wasteland of rubble, with hundreds of thousands surviving the winter cold in tents and makeshift shelters.

As his inauguration approached, Trump repeated his demand that a deal be done swiftly, warning repeatedly that there would be “hell to pay” if the hostages were not released. His Middle East envoy Steve Witkoff worked with President Joe Biden’s team to push the deal over the line.

In Israel, the return of the hostages may ease some of the public anger against Prime Minister Benjamin Netanyahu and his right-wing government over the Oct. 7 security failure that led to the deadliest single day in the country’s history.

The conflict spread across the Middle East, with Iran-backed proxies in Lebanon, Iraq and Yemen attacking Israel in solidarity with the Palestinians. The deal comes after Israel killed the top leaders of Hamas and Lebanon’s Hezbollah in assassinations which gave it the upper hand.