The head of Russia's space agency used strong language to criticize U.S. State Department members for failing to mention Yuri Gagarin in a post marking 60 years since his historic spaceflight.
On Monday, Russia led by President Vladimir Putin marked the 60th anniversary of the legendary flight that made Gagarin the first human in orbit.
The U.S. State Department issued a Facebook post commemorating 60 years since the flight as well as "technological progress and international cooperation, which are facilitated by space exploration."
The short post in Russian did not mention Gagarin, who gave the Soviet Union a major victory in the Cold War-era space race against the United States.
"A**holes. Superpowers do not behave that way," Roscosmos head Dmitry Rogozin wrote in response on Twitter late Monday.
A brash and brazen former diplomat, Rogozin is known for provocative tweets and boisterous claims.
In 2014, Rogozin, then a deputy prime minister in charge of space, responded to Western sanctions on Russia with a tweet suggesting the United States could send its astronauts to space "using a trampoline."
Russia at the time was the only country capable of delivering crews to the International Space Station (ISS).
"The trampoline is working," U.S. billionaire Elon Musk quipped in 2020 after his company SpaceX successfully launched a crew to the ISS.
Gagarin's flight on April 12, 1961 lasted 108 minutes, the time it took to complete one loop around the Earth.
Twenty-three days later, Alan Shepard became the first American in space. His flight on Freedom 7 on May 5, 1961 was suborbital.