The Russian Embassy in the U.S. did not mince words in a tweet late Monday warning Washington not to deploy hypersonic missiles in Europe. 

The tweet begins with a red exclamation point and reads: "We would like to remind @PentagonPressSec that potential deployment of any [American flag] hypersonic [missile] in Europe would be extremely destabilizing. Their short flight time would leave [Russian flag] little to no decision time and raise the likelihood of inadvertent conflict."

The tweet comes as the U.S. reportedly turned its attention away from a railgun to hypersonic technology.

John F. Kirby, the Pentagon press secretary, held a press conference on Monday and was asked by a reporter about Russia’s claim that it successfully tested a Tsirkon hypersonic cruise missile. Reuters reported that Russian President Vladimir Putin said the weapon has no equal in the world. 

Of course, in a military conflict, the country that can strike first and most decisively has the upper hand. While the U.S. is believed to have the world’s fiercest submarine fleet, Russia’s hypersonic advancement seems to have been noticed, especially since these missiles are apparently being designed to have nuclear capabilities.

BIDEN TELLS PUTIN TO 'DISRUPT' RANSOMWARE GROUPS OPERATING OUT OF RUSSIA

"We’re certainly aware of President Putin’s claims," Kirby said, according to a transcript from his press conference. "And while I won’t be getting into specifics or providing any kind of an analysis on his claims, it’s important to note that Russia’s new hypersonic missiles are potentially destabilizing and pose significant risks because they are nuclear-capable systems."

In this photo taken from video distributed by Russian Defense Ministry Press Service, a new Zircon hypersonic cruise missile is launched by the frigate Admiral Gorshkov of the Russian navy from the White Sea, in the north of Russia, Russia, Monday, July 19, 2021. (Russian Defense Ministry Press Service via AP)

Kirby said the U.S. is working "closely with allies and partners, including NATO, to try to check those destabilizing activities."

CLICK HERE TO GET THE FOX NEWS APP

The Pentagon did not immediately respond to an email from Fox News shortly after the Russian embassy tweet.

Al Jazeera reported that the missile was fired from a warship in the White Sea. Russia claimed that the missile traveled seven times the speed of sound and nailed a target about 217 miles away.

The Associated Press contributed to this report