The so-called "enhanced blast" weapon uses similar technology used in the US "bunker busting" bombs and the devastating bombs dropped by the Russians to destroy the Chechen capital, Grozny.
Such weapons are brutally effective because they first disperse a gas or chemical agent which is lit at a second stage, allowing the blast to fill the spaces of a building or the crevices of a cave. When the US military deployed a version of these weapons in 2005, DefenseTech wrote an article titled, "Marines Quiet About Brutal New Weapon." Raw Story
Some countries do have WMD