Sen. Lindsey Graham (R-S.C.), a leading Senate voice on foreign policy issues, praised President Trump Wednesday for getting Ukraine to agree to a 30-day ceasefire, but expressed strong skepticism that Russia would accept the proposal.

“It is clear to me that [Ukrainian] President [Volodymyr] Zelensky is willing to make peace. As Secretary Rubio said, the ball is now in Russia’s court. I am extremely skeptical that Russia will accept the ceasefire and I am very doubtful they want to end this war,” he said in a statement posted on X, referring to Secretary of State Marco Rubio’s comment that “Ukraine. Is ready to stop shooting and start talking.”

Ukraine on Tuesday said it would accept a 30-day truce with Russia if the Trump administration lifts its pause on military aid and intelligence sharing with Ukraine.

Graham said “Zelensky has passed the test of wanting peace.”

“It is now up to [Russian President Vladimir] Putin to show his cards,” he added.

Graham said he would introduce legislation to place “bone-breaking sanctions” and tariffs against Russia is they reject the ceasefire offer.

“If they do not pursue the ceasefire with the same vigor as Ukraine, there will be hell to pay. I expect overwhelming bipartisan support for my proposal,” he said.

Rubio said that Russia would be the “impediment” to peace if it rejects the proposal.

“If they say no, then we’ll unfortunately know what the impediment is to peace here,” he said.

Mike Waltz, Trump’s national security adviser, said Tuesday that Ukraine’s delegation made clear “that they share President Trump’s vision for peace.”

Russian launched a missile strike on Zelensky’s hometown, Kryvyi, after Ukraine agreed to the ceasefire offer. The attack killed a woman and injured several civilians.