Because of this, the bomb's blast and pressure wave have a similar effect to a small tactical nuclear weapon.

They quoted Tom Burky, a senior research scientist at Battelle, saying "It's not even clear what kind of weapon the Russians tested."

[8] John Pike, an analyst at the think tank GlobalSecurity, says he believes the weapon is roughly as powerful as the Russians claim.

[7] Robert Hewson, an editor for Jane's Information Group, told the BBC it was likely that FOAB indeed represented the world's biggest non-nuclear bomb.

"You can argue about the numbers and how you scale this but the Russians have a long and proven history of developing weapons in the thermobaric class", he says.