Russia has successfully launched a hypersonic missile, Russian President Vladimir Putin announced earlier this month.
Russia's Defense Ministry said the missile was launched from a MiG-31 aircraft that took off from an airfield in southwestern Russia.
"The launch went according to plan: the hypersonic missile hit its target," the ministry said.
However, the news is being downplayed by top US Defense Department officials, including Secretary James Mattis.
While on a plane traveling to the Middle East, Mattis said that nothing Putin showed off changed anything from the Pentagon's perspective.
"I saw no change to the Russian military capability and each of these systems that he's talking about that are still years away, I do not see them changing the military balance. They do not impact any need on our side for a change in our deterrence posture," he said.
In a recent speech, Putin claimed his nuclear weapons could be used to attack the United States.
Mattis called this news "disappointing but unsurprising," adding that it does not alter the Pentagon's strategic plan to counter Moscow.
"At the end of the day, they can sink all of that money in," he said. "It does not change my strategic calculation. I just assumed it would all happen at great expense to the Russia people."