NEWEST GAZA

GAZA. Israel improved airstrikes on the Gaza Strip and sealed it off from food, fuel, and other supplies Monday in retribution for a bloody invasion by Hamas militants, as the war’s death toll rose to nearly 1,600 on both sides. Hamas also escalated the conflict, pledging to kill captured Israelis if invasions target civilians without warnings.

In the war’s third day, Israel was still finding bodies from Hamas’ stunning weekend invasion of southern Israeli towns. Rescue workers found 100 bodies in the tiny farming community of Beeri — around 10% of its population — after a long prisoner impasse with gunmen. In Gaza, tens of thousands fled their homes as rigorous airstrikes balanced facilities.

The Israeli military said it had mainly gained control in the south after the attack caught its vaunted military and intelligence apparatus completely off guard and led to fierce battles in its streets for the main time in decades. Hamas and other militants in Gaza say they are carrying more than 130 soldiers and civilians grabbed from inside Israel.

Israeli tanks and drones were deployed to patrol against violations in the Gaza border fence to prevent new incursions. Thousands of Israelis were vacated from more than a dozen towns near Gaza, and the military convened 300,000 reservists — a massive mobilization in a short time.