The Israeli military has confirmed that Hamas leader Yahya Sinwar, mastermind behind the Oct. 7, 2023 attack that triggered the ongoing war in Gaza, has been killed in an Israeli military operation."Eliminated: Yahya Sinwar," the Israel Defense Forces wrote Thursday in a post on social media.Israel's foreign minister said Sinwar's identity was confirmed after authorities conducted a DNA test on his body. He was among two others who were also killed in the Israeli military operation.RELATED STORY | Biden: US troops to "remain postured" in the Middle East as tensions escalateSinwar's death marks a significant development in Israel's yearlong war against Iranian-backed Hamas militants in Gaza. However, it could also complicate Israeli efforts to get dozens of Israeli hostages freed from Hamas captivity.The IDF said in a statement that "there were no signs of the presence of hostages" in the area where Sinwar was killed. After his death was confirmed, Families of American Hostages Held In Gaza released a statement demanding the immediate release of all hostages."It is now time for every single hostage held in Gaza to be returned to their families. No more delays and no more demands," the statement reads. "Whether through negotiation or by any other means, all parties must immediately seize this opportunity to bring home the 101 remaining hostages, including seven Americans, before it's too late. The elimination of this brutal terrorist is a step toward justice. But true victory for Israel, its allies, and for the world will only be achieved when every hostage is released and the suffering of civilians in Gaza ends."RELATED STORY | Understanding the dynamics of a potential Israel-Hamas cease-fireMeanwhile, U.S. troops are set to remain stationed throughout the Middle East as tensions continue to escalate in the region. In a letter sent to Congressional leadership earlier this week, President Joe Biden explained that troops are to "remain postured" in order to "protect Israel from Iranian and Iranian-aligned threats."The latest actions from the Biden administration come as Israel's year-long war against Hamas in Gaza has expanded into a multi-front operation to also combat Iranian-backed Hezbollah militants in Lebanon. Late last month, the Israeli military said it had launched a "limited, localized" ground operation into the country, that has since boiled over into all-out war between the two sides and risks sparking an even wider regional conflict.