Israeli leaders celebrated the killing of Hamas leader Yahya Sinwar, who was assassinated by Israeli forces on Thursday.

Israel President Isaac Herzog commended the Israel Defense Forces for the killing and said Israel must act in every way possible to bring back the remaining 101 hostages being held by Hamas in Gaza.

"Sinwar, the mastermind behind the deadly October 7th attack, has for years been responsible for heinous acts of terrorism against Israeli civilians, citizens of other countries, and the murder of thousands of innocent people. His evil endeavors were dedicated to terror, bloodshed, and destabilizing the Middle East," Herzog said in a statement.

Israeli Minister of Defense Yoav Gallant also saluted IDF soldiers.

"The elimination of Sinwar joins a long series of eliminations -- from Nasrallah to Muhammad Deif and many more. We will pursue and eliminate our enemies. Sinwar died while beaten, persecuted and on the run -- he didn’t die as a commander, but as someone who only cared for himself," Gallant said in a statement.

"This is a clear message to all of our enemies -- the IDF will reach anyone who attempts to harm the citizens of Israel or our security forces, and we will bring you to justice," Gallant said.

Benny Gantz, the former IDF chief of staff and former minister of defense, applauded the killing, but said "the mission is not over."

"The IDF will continue to operate in the Gaza Strip for years to come, and now the series of achievements and the elimination of Sinwar must be taken advantage of to bring about the return of the abductees and the replacement of Hamas' rule. On this day, we will also remember the painful price of the war, all the murdered and martyrs, and we will strengthen all our heroic soldiers who have been working for over a year in all arenas to ensure that never again," Gantz said.

-ABC News' Jordana Miller

Hamas political leader Yahya Sinwar was killed by Israeli forces on Thursday, Israel Foreign Minister Israel Katz confirmed in a statement.

"The master murderer Yahya Sinwar, who is responsible for the massacre and atrocities of October 7, was killed today by IDF soldiers," Katz said.

-ABC News' Guy Davies

Egypt replaced the head of its general intelligence agency -- who played an instrumental role in brokering a Gaza cease-fire deal -- amid stalled negotiations. Deputy Hassan Rashad was named as new head of the agency.

Abbas Kamel, a longtime confidant and close aide to President Abdel Fattah al-Sisi, had headed the general intelligence agency since 2018 and was seen as the country’s second-most powerful figure.

Sisi relied heavily on Kamel for managing foreign policy affairs, including conflicts in Gaza and Sudan, as well as domestic security issues such as a wide-scale crackdown on dissent.

The change comes amid stalled negotiations for a cease-fire in the ongoing war in Gaza, which has spread into Lebanon. Kamel was a lead negotiator in the mediation efforts by Egypt, the U.S. and Qatar to end to the yearlong conflict. He played a key role in the diplomacy that led to a weeklong truce in November 2023.

Kamel will now take up a post of presidential adviser and envoy, as well as general coordinator of security services, according to a presidency statement.

-ABC News' Ayat Al-Tawy

The Israel Defense Forces are "checking the possibility" that Hamas leader Yahya Sinwar is one of the three militants it killed in Gaza on Thursday.

"At this stage, the identity of the terrorists cannot be confirmed," the IDF wrote in a post to X. "In the building where the terrorists were eliminated, there were no signs of the presence of hostages in the area. The forces that are operating in the area are continuing to operate with the required caution."

The 62-year-old has served as Hamas' leader in Gaza since 2017 and assumed leadership of the group's political bureau after the Israeli assassination of Ismail Haniyeh in Iran this July.

-ABC News' Guy Davies