Israel and Hamas are at war. Here's what to know about Hamas. | USA TODAY

Israel is at War against Hamas after unprecedented attacks against civilians and soldiers. Here's what to know.
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As Israel continued to press its assault on Gaza after Hamas infiltrated by land, sea and air over the weekend, killing and capturing over 1,000 Israelis, the spotlight has focused on the militant group.
Israel's leaders have vowed retaliation, and Prime Minister Benjamin Netanyahu said Hamas "will pay an unprecedented price."