Retired astronaut Scott Kelly says he’s backing down from his Twitter feud with the head of the Russian space agency after a NASA official urged restraint.

Kelly and Roscosmos Director General Dmitry Rogozin have engaged in a heated back-and-forth over the past couple of weeks, with Russia’s war against Ukraine at the heart of it. 

After Rogozin shared a video of the U.S. flag being removed from a Russia rocket March 2, 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.”

According to a screenshot posted by Kelly, Rogozin posted — and then quickly deleted — a tweet saying: “Get off, you moron! The death of the International Space Station will be on your consciousness.”

The feud escalated further when Rogozin posted a video edited to appear to show cosmonauts waving goodbye to U.S. astronaut Mark Vande Hei before detaching themselves from the space station, which Kelly viewed as a threat that Vande Hei, who is is scheduled to fly back to earth with the Russians on March 30, might be left behind. 

NASA said this week that the plans for Vande Hei’s travel home remain unchanged. On Tuesday, Vande Hei broke the U.S. single spaceflight record of 340 days, previously held by Kelly.

“When I saw Roscosmos produce and then later release a video leaving Mark Vande Hei … they're basically saying they're no longer going to be responsible for a person that they agreed to take care of,” Kelly told CNN’s “New Day” on Wednesday. “And it just really outraged me. And I had to speak up about it and do it in a way that would get Roscosmos’ attention.”

But a high-ranking NASA official sent an email last week urging caution from former astronauts before “attacking our Russian partners,” CNN, which obtained a copy of the email, reported. The network agreed not to disclose the name of the official who wrote it.

"As Americans, each of us enjoys freedom of speech and you are all empowered to speak your mind," the email reads. "However, please know that as former NASA astronauts, your words carry additional weight and attacking our Russian partners is damaging to our current mission."

Kelly — the twin brother of Sen. Mark Kelly, D-Ariz., also a former astronaut — acknowledged the email in an interview with CNN and said he would heed NASA’s warning. 

“I respect NASA, I respect their mission, I understand they're in a very difficult spot, and I respect the man that sent that email,” he said. “So I decided I'm not going to try to make NASA's job any harder than it already is because they do have a hard job. So I did back off Rogozin. At least for now.”

Kelly said he “absolutely” wants to see the United States and Russia continue to work together in space. 

“It is, like, basically the last thing that ties our country and really the rest of the free world to Russia in a peaceful and cooperative way,” he said.

But Kelly continues to use his Twitter account to speak out against the war. The ex-astronaut, who speaks and often tweets in Russian, says there are many Russians among his 5.3 million followers.

“My goal is just to get the message to Russian speakers in Russian and around the world about what is going on,” he said. “The real news.”

Kelly also said he returned a medal that former Russian President Dmitry Medvedev awarded him for his work in space.

“After this happened, I was just kind of disgusted to have it,” Kelly said. “So I told now Deputy Prime Minister Medvedev that I was going to return this award and maybe he could give it to a Russian mother whose son was killed."

“The very same day, I mailed it to the Russian Embassy in Washington D.C.," he added.