What is a ‘vacuum bomb’ that Ukraine says Russia is using?

Ukraine’s ambassador to the US and human rights groups said on Monday that Russia has been attacking the country with vacuum bombs and cluster bombs. Amnesty International and Human Rights Watch said that Russian troops are using widely banned cluster munitions. Amnesty also accused them of attacking a preschool where civilians had taken shelter. 

Ukrainian ambassador Oksana Markarova told reporters that Russia has used a thermobaric weapon, which is also known as a vacuum bomb, in its invasion of her country. "They used the vacuum bomb today," Markarova said on Monday, after a meeting with lawmakers. "...The devastation that Russia is trying to inflict on Ukraine is large."

CNN had also reported that one of its teams spotted a Russian thermobaric rocket launcher near the Ukrainian border on Saturday. 

White House Press Secretary Jen Psaki said that there have been reports on the same but she does not have any confirmation on it yet. She said if it were true, it would be a potential ‘war crime’. 

What is a vacuum bomb?

A thermobaric weapon or a vacuum bomb is used to suck in the oxygen from the surrounding area to generate a high-temperature explosion. The blast wave produced hence is significantly longer in duration as compared to a conventional explosive. It is also capable of vaporising human bodies. 

Fuel-air explosives or FAE were first developed and used in Vietnam by the US, according to a Human Rights Watch report from 2000. It added that soon Soviet scientists developed their FAE weapons and used them against China in 1969. Since then, the research and development have continued and Russians hold a wide range of third-generation FAE warheads.

The report quoted a 1993 study by the US Defence Intelligence Agency saying, “The kill mechanism against living targets is unique--and unpleasant... What kills is the pressure wave, and more importantly, the subsequent rarefaction [vacuum], which ruptures the lungs.... If the fuel deflagrates but does not detonate, victims will be severely burned and will probably also inhale the burning fuel. Since the most common FAE fuels, ethylene oxide and propylene oxide, are highly toxic, undetonated FAE should prove as lethal to personnel caught within the cloud as most chemical agents.”

Another report quoted said that those near the ignition point are obliterated, while those on the fringe are “likely to suffer many internal, and thus invisible injuries”.

Amnesty International said international humanitarian law prohibits the use of inherently indiscriminate weapons such as cluster munitions. Launching indiscriminate attacks that kill or injure civilians constitutes a war crime.

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