Yury Borisov, the deputy prime minister in charge of military development, told Russian TV that a laser prototype called Zadira was being deployed in Ukraine and had burned up a Ukrainian drone within five seconds at a distance of 5km (three miles).

This was in addition to a previous laser system called Peresvet - named after a medieval Orthodox warrior monk - which could be used to dazzle satellites orbiting high above Earth and prevent them from gathering information.

"If Peresvet blinds, then the new generation of laser weapons lead to the physical destruction of the target - thermal destruction, they burn up," Mr Borisov said.

However, an official with the US Department of Defense said he had not seen "anything to corroborate reports of lasers being used" in Ukraine.

Meanwhile, Ukrainian President Volodymyr Zelensky mocked the Russian claim, comparing it to the so-called "wonder weapons" that Nazi Germany claimed to be developing during World War Two.

"The clearer it became that they had no chance in the war, the more propaganda there was about an amazing weapon that would be so powerful as to ensure a turning point," he said in a video address.

"And so we see that in the third month of a full-scale war, Russia is trying to find its 'wonder weapon'... this all clearly shows the complete failure of the mission."

What laser weapons can - and can't - do

Little is known about the Zadira laser programme, but in 2017 Russian media said state nuclear corporation Rosatom had helped develop it as part of a programme to create weapons based on new physical principles, news agency Reuters reported.

But there is at least one country which has developed a laser weapon. Last month Israel released video showing a laser system shooting down rockets and drones.

Prime Minister Naftali Bennett said it could shoot down drones, mortars and rockets for just $3.50 (£2.80) a shot. "It may sound like science fiction, but it's real," he said.

But missile defence expert Dr Uzi Rubin from the Jerusalem Institute for Strategy and Security (JISS) said laser weapon technology would not alter the balance of power on the battlefield in Ukraine.

"Zelensky is right - it's no wonder weapon," he told the BBC. "It took them several seconds to shoot the UAV down. There are much better ways to do it, to use a Stinger or any anti-aircraft missile would have been cheaper, faster and longer range."

Lasers work by sending out a beam of infrared light that heats up its target until it combusts. Dr Rubin said the power of even advanced laser weapons was still too weak to make a significant difference on the battlefield, and such weapons had a low "kill rate".

"It's not like in Star Wars where they point a laser gun at the bad guys and quickly push a button and the bad guy explodes. In reality, it's more like a mere microwave oven. If you want to make a cup of water boil it takes some time. The laser is the same. You need to put it on the target and wait until it heats up and destroys it," he said.

The laser can only focus on one target at a time, Dr Rubin said, while missile defence systems can engage multiple incoming targets simultaneously.

Additionally, lasers are neutralised by bad weather because they don't work in rain or snow and cannot penetrate cloud.

However Israel's "Iron Beam" does have a rationale, he said, but mainly as a way of saving money. Israel's expensive Iron Dome interceptor missiles are designed to protect major cities from incoming missiles, rather than mortar rounds or drones.

"Missile warfare is a war of resources. It's cheaper to make the rockets than to defend against them. So whatever you can do to reduce the costs of defending is useful," he said.

"Energy weapons can be useful in reducing costs - but it's not going to make a revolution."

Additionally, Russia could use lasers on the battlefield to blind Ukrainian soldiers, retired Australian army major general Mick Ryan told the Washington Post, although this is banned under a 1995 protocol added to the UN treaty that prohibits weapons causing excessive injury or having indiscriminate impact.

Russia, the US, UK and others are signatories to the protocol.

The 'wonder weapons' backstory

Mr Zelensky's reference to "wonder weapons" - Wunderwaffen - is about Nazi German propaganda disseminated at a time when the war was going badly for them.

The propaganda ministry, run by Joseph Goebbels, tried to boost morale and keep Germans believing in victory by hinting that special new weapons were coming that would turn the war decisively in their favour.

When the Nazis began firing their V-1 flying bomb at Britain, the Nazi propaganda machine began saying that it would force Britain to drop out of the war, according to Michael Neufeld, a senior curator at the Smithsonian Museum in Washington.

"The propaganda said we're going to get our revenge and turn this around. I'm not surprised at all that Zelensky might refer to this WW2 background," he told the BBC.

There was disillusionment when that did not happen - but the idea that these new weapons could have proved decisive lives on even today, says Mr Neufeld, who says he has spent a career fighting it.

However, he cautioned against drawing too direct a parallel with Russia heralding its laser weapon, saying that Moscow has consistently talked its weaponry up with its references to nuclear and hypersonic arms.

"It may be premature to see this as a case of being reactive because the war is going badly," he said.

"At the beginning of the war, they assumed that talking about these new weapons would intimidate and force Ukraine to quit. And now they may be turning it around and saying they are still superior."

sapientia:
The strongest man in the whole world expect us to believe he had such weapon and waited till now to bring it out

Is such weapon not supposed to be on the Flag Ship that was harassed by drones, distracted and taken out by cheap missiles?

If Russia have such weapon, Putin should apologise to all his soldiers that have been roasted in their tanks by drones