Israel increased airstrikes on the Gaza Strip and sealed it off from food, fuel and other supplies Monday in retaliation for a bloody incursion 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 attacks targeted civilians without warnings. MORE: https://www.cbs8.com/article/news/nation-world/israel-hamas-conflict/israel-hamas-conflict-gaza-strip/507-1b9351ac-5ad0-42d0-bdee-adf1b811a4bb