A senior Russian official slammed United States President Donald Trump’s proposal that he could militarily aid Ukraine in exchange for access to its valuable mineral rights.

“If we call things as they are, this is a proposal to buy help — in other words, not to give it unconditionally, or for some other reasons, but specifically to provide it on a commercial basis,” Kremlin spokesperson Dmitry Peskov told reporters Tuesday.

“It would be better of course for the assistance to not be provided at all, as that would contribute to the end of this conflict,” he added, about a war that was instigated by Russia.

Trump announced Monday that he was “looking to do a deal with Ukraine” in which the U.S. would provide military aid for the war against Russian President Vladimir Putin in exchange for Ukraine’s “rare earths.”

“We’re investing hundreds of billions of dollars. They have great rare earths, and I want security of the rare earths,” he said in Washington, adding that Ukraine is “willing to do it.”