Hamas leader Yahya Sinwar, architect of the group's cross-border raids in 2023 that became the deadliest day in Israel's history, was killed in combat, Khalil Al-Hayya, deputy Gaza Hamas chief and the group's chief negotiator, said on Friday. Sinwar's death, which follows Israeli assassinations of other Hamas leaders and commanders, will deal a huge blow to the Islamist group which has faced relentless air strikes since it attacked Israel on Oct. 7, 2023, killing 1,200 people, according to Israeli tallies. It also dragged about 250 people back to Gaza, creating a hostage crisis for Israeli Prime Minister Benjamin Netanyahu 's government which has vowed to eliminate Hamas. Sinwar will be remembered as a ruthless enforcer among Palestinians who collaborated with Israel and an implacable enemy of the country which jailed him for many years. Sinwar was named the group's paramount leader on August 6, as a successor to former political chief Ismail Haniyeh, who was assassinated in Tehran on July 31