Tech billionaire Elon Musk’s plan to bomb Mars to make it suitable it for human life is a front to deploy nuclear weapons in space, Russia’s space chief said Wednesday.

The SpaceX founder and CEO has occasionally floated his controversial plan to terraform the Red Planet by setting off thermonuclear explosions above the planet’s polar caps and evaporating the frozen carbon dioxide stored there. According to Musk, this would trigger the greenhouse effect, raising the planet’s average temperatures enough to support human life.

“We understand that one thing is hidden behind this demagogy: This is a cover for the launch of nuclear weapons into space,” Dmitry Rogozin, the head of Russian state space agency Roscosmos, said in a YouTube interview with pro-Kremlin television pundit Vladimir Solovyov. 

He slammed Musk’s idea as “inhumane,” saying it would “destroy” the planet.

“We see such attempts, we consider them unacceptable and we will hinder this to the greatest extent possible,” he said, adding that Russia is readying a response and that international regulations ban the deployment of any weapon into space.

Earlier this month, Roscosmos executive director for advanced programs and science Alexander Bloshenko told the state-run TASS news agency that Musk’s plan would require the detonation of more than 10,000 nuclear warheads. Musk responded with a tweet that simply said “No problem.” 

Rogozin has traded barbs with the SpaceX CEO several times in the past, accusing him of trying to squeeze Moscow out of the carrier rockets market by lowballing prices for commercial space flights.

His comments come a day after SpaceX was forced to delay the landmark launch of its Dragon spacecraft to the International Space Station over inclement weather. If successful, the mission will signal that the U.S. is no longer dependent on Russia’s Soyuz rockets for access to space.