After multiple alleged Israeli airstrikes on pro-Iranian paramilitary bases in an around Baghdad over the past months, tensions within the US-Iraqi coalition are at a boiling point, especially as the US command stands accused of "looking the other way" while its close ally Israel mounts unprecedented drone operations over Iraq's sovereign airspace. 

So the Pentagon is desperate to show it's presence can be justified at a moment of the coalition's most intense scrutiny in years, also as some US politicians question the continuing military presence there. 

It announced Tuesday American warplanes dropped 40 tons of bombs on an ISIS "infested" island in the Tigris River, and released video of the massive carpet bombing operation: