The Russian bombs and US bombs can be set to detonate upon impact. The shock wave basically vibrates the bunker into dust particles in a millisecond.How do those work against underground bunkers?Bombing...unless you use nukes...is not THAT efficient.In a week the entire city of Raqqa will be dust.Look for France and Russia to take the lead in the almost WWII style of carpet bombing the city of ISIS which serves as the Capitol of the Islamist Caliphate in Raqqa. Reports are coming in that it has already started.
Really? Some thermobarics would work wonders.