Elon Musk has taken aim at the Russian space agency after its boss claimed Americans would need broomsticks to get to space.
Russian space agency Roscosmos head Dmitry Rogozin said Russia would no longer supply rocket engines to the US after President Joe Biden imposed heavy sanctions over the war in Ukraine.
"In a situation like this, we can't supply the United States with our world's best rocket engines," Rogozin said on state-run TV.
"Let them fly on something else, their broomsticks, I don't know what."
When the Russian space boss criticised Musk for offering Starlink internet in the Ukraine he responded: "Ukraine civilian internet was experiencing strange outages – bad weather perhaps? – so SpaceX is helping fix it."
Starlink, SpaceX's satellite internet service, now has more than 2000 satellites in orbit.
Musk warned Starlink users in Ukraine to turn on the system "only when needed" because they could be targeted amid the invasion.
Musk has been outspoken about Russia's invasion of Ukraine.
He has called on the United States to increase its domestic oil output in response to the invasion, while also acknowledging that his electric car company would be negatively affected by that move.
"Hate to say it, but we need to increase oil & gas output immediately," Musk said.
"Extraordinary times demand extraordinary measures."
Musk added, "Obviously, this would negatively affect Tesla, but sustainable energy solutions simply cannot react instantaneously to make up for Russian oil & gas exports."
Russia is the producer of one out of every 10 barrels of oil consumed by the world, according to the New York Times, making it the third-largest oil producer in the world.
On Friday, Secretary of State Antony Blinken downplayed the notion of sanctioning Russia's energy sector arguing that the United States has "no strategic interest" in doing so.