Astronaut Senator Mark Kelly issues furious response after Elon Musk calls him a 'traitor' again for visiting Ukraine

US Senator Mark Kelly has hit back for the second time after Elon Musk called him a 'traitor' for visiting Ukraine.

The former astronaut and Navy veteran does not seem to be on good terms with the Tesla mogul after the pair butted heads again amid rising tensions over Ukraine.

Since Donald Trump took office in January, America's relationship has gone from bad to worse with the waring nation, and particularly after Republican president accused President of Ukraine Volodymyr Zelenskyy of 'gambling with World War 3' during a meeting in the Oval Office. He also went on to cut military aid to the country temporarily.

Soon after, Musk - who leads the Department for Government Efficiency (DOGE) within Trump's administration - began to take issue with the Democrat Senator for Arizona, Kelly, after he went to Ukraine amid the ongoing peace talks with Russia earlier this month.

Mark Kelly had some strong words for Elon Musk (Drew Angerer/Getty Images)

At the time, Kelly wrote on Twitter: "Just left Ukraine. What I saw proved to me we can’t give up on the Ukrainian people. Everyone wants this war to end, but any agreement has to protect Ukraine’s security and can’t be a giveaway to Putin.

"Finally, if we stand with Ukraine they will be there for us. This country has a fighting spirit and a depth of experience and kickassness unmatched anywhere in the world today. These are the people you want in your corner. My goal in the Senate is and will continue to be to keep us out of wars."

This led to Musk calling him a traitor, and Kelly hit back stating: "Traitor? Elon, if you don’t understand that defending freedom is a basic tenet of what makes America great and keeps us safe, maybe you should leave it to those of us who do."

Now, Kelly has snapped back at Musk again after the billionaire doubled down on his insult.

Musk’s second jab came when he told Fox News: “I think somebody should care about the interests of the United States above another country, and if they don’t they’re a traitor.”

The US Senator has visited Ukraine several times (Twitter/@SenMarkKelly)

Kelly has since told CNN that Musk was aligning himself with ‘a bunch of billionaires’ who have values that are ‘much closer to Russia.’

“I don’t even know if he deserves a response.

“What I will say is that I’ve spent an entire career standing up for our country, defending our country, flying in combat over Iraq, flying in space on the space shuttle, serving in the United States Senate.”

Kelly continued: “My entire life has been about serving this country, and I always stand with the best interests of our nation. And I will tell you this … standing with our allies and standing up for democracy is in the best interest of the United States.”

Finally, Kelly shared that he wants the war to end just like everyone else.

He said: “I want this thing to end as much as anybody. But he throws this ‘traitor’ word around — at least with regards to me — fairly freely.

"I don’t think he’s a serious guy, and he hasn’t given this a lot of thought.”