Video from the Islamic State uploaded to a social media website on Monday sends a message from its fighters to Americans.<br/> <br />It reads: "We will drown all of you in blood."<br/> <br />The militant group has warned that it will attack Americans anywhere if U.S. airstrikes hit Islamic State militants.<br/> <br />Recent U.S. airstrikes on northern Iraq have helped Iraqi and Kurdish forces recapture territory that was seized by the Islamist militants.<br/> <br />The fighters have threatened to march on Baghdad, and their latest advance sent tens of thousands of ethnic Yazidis and Christians fleeing for their lives.