The Russian air force has tested a giant fuel-air bomb which the military says is the biggest non-nuclear explosive device in the world.
Russian TV showed a Tupolev bomber dropping the bomb over a test range, a powerful explosion and a four-storey building reduced to rubble.
Claims it is bigger than the Moab, a US device of similar destructive power, seem plausible, analysts say.
Such bombs are mainly designed to destroy underground targets.
Fuel-air bombs, technically known as thermobaric devices, generally detonate in two stages: a small blast creates a cloud of explosive material, which is then ignited with devastating effect.
The name Moab officially stands for Massive Ordnance Air Burst but has unofficially been interpreted as Mother Of All Bombs.
The Russian bomb, which has no known official name, has been dubbed Father of All Bombs by its designers, Russia's Channel One News says in its report.
It contains about seven tons of high explosives compared with more than eight for the Moab but is four times more powerful because it uses a new type of explosive developed with the use of nanotechnology, according to the channel.
"Test results of the new airborne weapon have shown that its efficiency and power is commensurate with a nuclear weapon," Gen Alexander Rukshin, Russian deputy armed forces chief of staff, told the channel.
It has, he says, "no match in the world".
Robert Hewson, editor of Jane's Air-launched Weapons, believes that the Russian claims are plausible given the country's track record in developing, and using, fuel-air devices.
It is believed the bomb has not been used in action
"I think the likelihood is that this is the world's biggest non-nuclear bomb," he told the BBC News website.
"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."
Russia used such weapons in Afghanistan and Chechnya, Hewson says, and he suspects that the bomb shown on TV was conceived for the Chechen conflict but never actually used because of the sheer scale of the destruction it could wreak.
He believes that the test blast was a "statement" by Russia comparable in its psychological effect to America's demonstration of the Moab just before the 2003 invasion of Iraq - a demonstration never followed up by its actual use.
"The Russians are in a phase of needing to make statements at the moment and have done the same thing," Hewson says.
The giant bomb was transported by a Tu-160 "Blackjack" supersonic bomber, itself in the news recently when Russia revived the Soviet practice of sending heavy bombers out on long-range flights.
Dropped from TU-160 bomber
Contains 7.8 tons of 'highly efficient' explosives, as effective as 44 tons of regular TNT, Russia says
Blast radius: 300 metres (990ft)
Blast and pressure wave has similar effect on the ground as a small nuclear device
Sources: AP, GlobalSecurity.org