Sen. Bernie Sanders (I-Vt.) on Thursday blasted former President Trump, saying it was “unsurprising” that he would praise Russian President Vladimir Putin and his “murderous invasion of Ukraine as an act of ‘genius.'” 

“It should concern us all that Putin is exactly the kind of leader Trump would like to be, and that so few Republicans have the courage to say this out loud,” the Vermont senator said in a post on Twitter.

Sanders, who has regularly clashed with Trump, tweeted his statement hours after Putin launched an invasion into Ukraine. 

Trump previously praised Putin during a Tuesday interview on “The Clay Travis and Buck Sexton Show” and said his strategy was “genius” and “pretty savvy.”

“I said, ‘How smart is that? He’s going to go in and be a peacekeeper,'” Trump said. “That’s the strongest peace force. We could use that on our southern border. That’s the strongest peace force I’ve ever seen. There were more army tanks than I’ve ever seen. They’re going to keep peace, all right.”

The Vermont senator’s comments come after Putin ordered a military invasion of Ukraine early Thursday morning, a move that garnered outrage from the international community. 

Russian forces entered Ukraine and explosions have occurred across the country. Ukraine says Russia has conducted strikes on its military infrastructure.

Sanders issued a statement on Tuesday calling a Russian invasion “an indefensible violation of international law, regardless of whatever false pretext he offers.”

“There has always been a diplomatic solution to this situation. Tragically, Putin appears intent on rejecting it,” he added.

Rep. Liz Cheney (R-Wyo.) and former national security adviser H.R. McMaster have also criticized the former president for his statements on the Russian leader.

“Former President Trump’s adulation of Putin today — including calling him a ‘genius’ — aids our enemies,” Cheney tweeted on Tuesday. “Trump’s interests don’t seem to align with the interests of the United States of America.”

McMaster issued a statement on Thursday saying that Putin was not worthy of praise following Russia’s attack on Ukraine.