SpaceX and Tesla CEO Elon Musk took to Twitter Thursday to lob verbal missiles at the head of Russia’s space agency, less than 24 hours after the country announced it was halting supplies of rocket engines to the U.S.

“American Broomsticks,” Musk tweeted, along with a video of a recent SpaceX launch and a screenshot of comments made by the head of the state space agency, which suggested the U.S. could not travel to space without Russian engines.

“In a situation like this we can’t supply the United States with our world’s best rocket engines. Let them fly on something else, their broomsticks, I don’t know what,” said Dmitry Rogozin on state Russian television.

Since the 1990s, 122 RD-180 engines have been delivered to the U.S., and 98 have already been used in NASA launches, according to Rogozin.

The move from Russia comes after the U.S. and its allies unleashed an unprecedented string of economic sanctions in the wake of their invasion of Ukraine. The sanctions have effectively crippled the Russian economy in the last week. 

Musk the internet provider to besieged Ukraine

Musk has inserted himself directly into the Ukrainian conflict while dealing with several legal issues in the U.S. 

Earlier this week, Musk delivered on a promise to Ukraine’s Deputy Prime Minister Mykhailo Fedorov by sending Starlink terminals into the war zone and helping the government connect to SpaceX’s satellite-based internet network, providing many Ukrainians with internet access. 

In the U.S., the SEC is reportedly probing Musk and his brother over insider trading while Tesla may be unionizing. On Thursday, Musk dared a union to hold a vote at a Tesla factory on the heels of President Joe Biden’s pro-labor State of the Union address.

It’s not the first time Musk has inserted himself into an international crisis that serves his business ventures and elevates his position as one of the most powerful people in the world. In early 2020, as the coronavirus pandemic began spreading around the world, Musk announced that Tesla would begin manufacturing ventilators to help hospitals battle COVID-19.

Musk’s Starlink provides internet lifeline

As of March 4, SpaceX confirmed it had deployed a total of 47 Starlink satellites to Ukraine. It’s unclear whether the company will send more in the coming weeks. 

On Thursday, Musk announced a series of updates to Starlink software meant to make it easier for Ukrainians to access the internet on the move. 

“Updating software to reduce peak power consumption, so Starlink can be powered from car cigarette lighter. Mobile roaming enabled, so phased array antenna can maintain signal while on moving vehicle,” Musk tweeted. 

Musk’s most recent update came in the form of a warning to Ukrainians using Starlink networks for internet access: “Important warning: Starlink is the only non-Russian communications system still working in some parts of Ukraine, so probability of being targeted is high. Please use with caution,” he said in a tweet.