Russia has used about 10 to 12 hypersonic weapons during the war in Ukraine, a senior US defense official said Tuesday, News.az   reports citing UNIAN.

Cautioning that the US does not have a "perfect count," the official said the number of hypersonic weapons Russia has used is "probably between 10 and 12 I think would be about right."

Though the official did not specify the dates and locations of the launches, US officials observed the first known combat use of the Russian air-launched Kinzhal hypersonic missile against a building in western Ukraine.

The official would not corroborate Ukraine's claim that Russia had fired Kinzhal missiles at Odesa over the weekend. Sergey Bratchuk, a spokesperson for the Odesa regional military administration, said Russia had fired three Kinzhal missiles at a "tourist infrastructure target."

The US has seen no indications that Russia used hypersonic weapons in these strikes, the US official said.

"Obviously, we've seen them use hypersonics in the past and hitting buildings, but I don't have anything to indicate that they were used in Odesa," said the official.

The Kinzhal missile, which became operational in 2017, has a claimed top speed of Mach 12, or about 9,000 miles per hour (more than 14,400 kilometers per hour). It is an air-launched version of the Russian Iskander short-range ballistic missile.

US officials downplayed the significance of the Russian use of their hypersonic Kinzhal missile. US Defense Secretary Lloyd Austin said he did not view it as "some sort of game changer" after the Russians announced the missile launch. Days later, Pentagon press secretary John Kirby said it was "hard to know what exactly the justification" was for the launch, since it targeted a stationary storage facility.

"That's a pretty significant sledgehammer to take out a target like that," Kirby said at the time. 

Russia also claimed it used Iskander missiles in April to strike weapons depots and Ukrainian military equipment.

Ukraine, on the other hand, claims Russia used Iskander missiles launched from Crimea to strike at a settlement in the Odesa district in early April.