(NewsNation) — Tensions have escalated between the United States and Russia, online as well as in real life.

Retired NASA astronaut Scott Kelly and Russian space chief Dmitry Rogozin, for example, have gone back and forth in a Twitter war of name-calling and potential removal of tweets.

The feud started March 2 when Rogozin, shared video showing a U.S. flag being removed from a Russian rocket with the caption “The launchers at Baikonur decided that without the flags of some countries, our rocket would look more beautiful.”

Kelly responded, “Your space program won’t be worth a damn. Maybe you can find a job at McDonald’s if McDonald’s still exists in Russia.”

Rogozin then deleted his response, according to a screenshot posted by Kelly, that said “Get off, you moron! The death of the International Space Station will be on your consciousness.”

“Dimon, why did you delete this tweet? You don’t want everyone to see how you are really just a child?” Kelly tweeted.

To which Rogozin responded “Mr. Scott Kelly! You needlessly provoke me. We are not familiar with you, but you address me on you (“ты”) and call me “Dimon”, although I do not know such a treatment and I will not allow you to behave like that with me. You are being defiant and destructive.”

In a tweet reply, Rogozin added: “Perhaps the dementia and aggression that you have developed is a consequence of the overload and stress of four flights into space. I invite you to undergo an examination at the Brain Institute of our Federal Medical and Biological Agency.”

A few days later, Russian news agency RIA Novosti shared a propaganda video, apparently edited by Rogozin.

The video appears to show cosmonauts waving goodbye to U.S. astronaut Mark Vande Hei, detaching themselves from the ISS.

“It kind of enraged me that the country that we had been in this international partnership for 20 years would take the time to make a video to threaten to leave behind one of the crew members they are responsible for,” Kelly said in an interview with The Wall Street Journal.

Vande Hei, who Tuesday will break the U.S. single spaceflight record of 340 days, is due to leave with two Russians aboard a Soyuz capsule for a touchdown in Kazakhstan on March 30.

Rogozin’s repeated threats to pull out of the International Space Station

“Mark is in no danger. The ISS is perfectly capable of supporting him for as long as he has to stay up there,” former NASA astronaut Jeffrey A. Hoffman said on NewsNation’s “Banfield.

“Mr. Rogozin, the head of Roscosmos, has really crossed a line as far as any acceptable etiquette for international cooperation. We have laws of astronaut safety that are part of the Outerspace treaty, the rescue of astronauts. And to suggest leaving somebody stranded in space, even though they’re in no physical danger, goes against all forms of cooperation.”

Although tensions have escalated between the United States and Russia, NASA insists Vande Hei’s homecoming plans at the end of the month remain unchanged.

Despite the feud online, Kelly believes that both sides can still “can hold it together” up in space.

“We need an example set that two countries that historically have not been on the most friendly of terms, can still work somewhere peacefully. And that somewhere is the International Space Station. That’s why we need to fight to keep it,” Kelly said in an interview with The Associated Press.