Israeli forces in Gaza killed Hamas leader Yahya Sinwar, a chief architect of last year’s attack on Israel that sparked the war, the military said Thursday. Troops appeared to have run across him unknowingly in a battle, only to discover afterwards that a body in the rubble was Israel’s most wanted man. Israeli leaders celebrated his killing as a settling of scores just over a year after Hamas-led militants killed some 1,200 people in Israel and kidnapped 250 others in an attack that stunned the country. They also presented it as a turning point in the campaign to destroy Hamas, urging its fighters to surrender and release some 100 hostages still in Gaza. “Hamas will no longer rule Gaza. This is the start of the day after Hamas," Prime Minister Benjamin Netanyahu said. U.S. officials expressed hopes for a cease-fire with Sinwar out of the picture. But eliminating him may not end the devastating war, during which Israel has killed more than 42,000 Palestinians and destroyed much of the Gaza Strip. His death is a crippling blow to the group. But Hamas has proven resilient to past losses of leaders. There was no immediate confirmation from Hamas of Sinwar’s death. Netanyahu has said Israel will keep fighting until hostages are free, and that it will keep control over Gaza long enough to ensure Hamas does not rearm — an effective occupation that raises the possibility of months or even years of continued fighting. Earlier this month Israel opened a new front in its war with Hezbollah, stepping up bombardment in Lebanon and launching a ground campaign against the Iran-backed militia after a year of trading cross-border fire. In his speech about Sinwar's death, Netanyahi said, “Our war is not yet ended.” President Joe Biden called Sinwar's death a “good day for Israel, for the United States, and for the world,” and he said it opens the way for "a political settlement that provides a better future for Israelis and Palestinians alike.” He said he would talk with Netanyahu "to discuss the pathway for bringing the hostages home to their families, and for ending this war once and for all.” Sinwar has been Hamas’ top leader inside the Gaza Strip for years, closely connected to its military wing while dramatically building up its capabilities. He was elevated to Hamas’ highest spot in July after his predecessor, Ismail Haniyeh, was killed in an apparent Israeli strike in the Iranian capital Tehran. In the past months, Israel has eliminated a string of senior figures from Hamas and Lebanon’s Hezbollah with airstrikes. Israel has claimed to have killed the head of Hamas’ military wing, Mohammed Deif, in an airstrike, but the group has said he survived. But in Sinwar's case, troops found him by chance. An Israeli military official said that Sinwar "engaged in combat” with Israeli troops operating in Gaza's southernmost city of Rafah, and was spotted running into a building. The army struck the building with tank fire. The army had suspected a number of top Hamas officials including Sinwar were in the vicinity, but Sinwar was not the target of that day's specific operations, said the official, speaking on condition of anonymity under military briefing rules. Visiting the site of the killing, Israeli army chief Herzi Halevi said that while the military had conducted “many special operations in this war where we had excellent information .... Here, we didn’t have that and the response was very, very strong.” Read more: https://www.9news.com/article/news/nation-world/israel-hamas-conflict/israel-investigating-whether-hamas-top-leader-sinwar-killed/507-7bb74089-e5a8-4a5b-90be-a1d68501f5e9 Video: CNN More local videos here: https://bit.ly/2Pa0d1l Subscribe to NEXT: http://bit.ly/2eP1GwI Stay connected: 9NEWS Website: http://www.9news.com/ Facebook: https://www.facebook.com/ilike9news Twitter: https://twitter.com/9NEWS Instagram: https://www.instagram.com/9newsdenver/ Download the 9NEWS App: https://www.9news.com/appredirect/ Sign up for the 9NEWSLETTER: https://www.9news.com/email 9NEWS (KUSA) is located in Denver, Colorado.