A senior U.S. defense official said on Friday that Russia could use thermobaric weapons, dubbed the "father of all bombs," in their ongoing invasion of Ukraine, the Daily Mail reported.
The weapons, commonly called vacuum bombs, are among the most powerful non-nuclear explosives ever developed. The U.S. version of the bomb reportedly costs more than $16 million.
"My fear would be that if they don't meet their timescale and objectives, they would be indiscriminate in their use of violence," the official said. "They don't adhere to the same principles of necessity and proportionality and rule of law that Western forces do."
The news comes amid the Kremlin's assault on Kyiv, where recent reports indicate a significant number of Russian casualties.
"Over 1,000 Russian soldiers killed today — Ukraine says it's the largest amount of casualties Russia ever sustained within this time period in a conflict it started," Anastasiia Lapatina, a journalist for the Kyiv Independent, wrote Friday on Twitter.
While Russian special forces are primarily in the suburbs of Kyiv, some reports indicating within city limits, the majority of Russia's heavy armor and ground troops are believed to still be further from the capital.
The U.S. official said that Russia appears to have lost some momentum in their invasion due to "greater resistance" by the Ukrainians than expected.
"They are not moving on Kyiv as fast as what we believe they anticipated they would be able to do. That said, they continue to try to move on Kyiv," the official added.
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