Hamas militants fired dozens of rockets into Israel on Monday, including a barrage that set off air raid sirens as far away as Jerusalem, after hundreds of Palestinians were hurt in clashes with Israeli police at a flashpoint religious site in the contested holy city.

The rocket fire drew heavy Israeli retaliation in the form of airstrikes in the Gaza Strip. Health officials said at least 20 people, including nine children, were killed in fighting, making it one of the bloodiest