Republican US Senator Thom Tillis on Sunday said President Donald Trump'sdiesel supply deal with Russia may be illegal and will put American lives at risk, adding to bipartisan criticism of the arrangement announced by the president on Friday.
Trump said that Russia had agreed to supply diesel to global markets, and his administration temporarily lifted US sanctions on Russian fuel that were designed to deprive Moscow of revenue for its war on Ukraine.
“I do believe there’s a legitimate case for saying the president’s not following the law,” Tillis, an influential Republican from North Carolina who is retiring from the Senate at the end of his term in January, told NBC's "Meet the Press" with Kristen Welker.
Prices for diesel — used for agriculture, heating homes and trucking — are near record highs and could hurt Trump's fellow Republicans in next month's congressional elections that will determine whether they maintain their thin majorities in Congress.
Analysts have said Trump's agreement with Moscow was unlikely to lead to sustained lower fuel prices.
US Treasury Secretary Scott Bessent told Fox News on Sunday that the Trump administration will follow through with the deal using existing legal authority, adding that the agreement was good for the American people and would bring prices down.
"We're going to do it with all the legal authorities we have. So, you know, anyone in Congress who says whether it's an old bill or the current Lindsey Graham bill (that) prohibits us from doing it is wrong," Bessent told the "Fox & Friends" program.
Trump last month signed a sweeping Russia sanctions bill into law, called the "Lindsey O. Graham Sanctioning Russia and Iran Act of 2026," to honor the South Carolina Republican who died in July. Graham, a longtime Russia hawk, was a staunchbacker of the legislation.
Tillis is not the first Republican to criticize the deal. Retiring Representative Don Bacon of Nebraska said on X on Friday that "propping up (Russian President Vladimir) Putin’s war economy is morally wrong as he uses that money to bomb cities."
Mike Pence, Trump's former vice president, called his decision to lift sanctions on Russian oil a "betrayal" of Graham’s legacy and urged the president to "rescind" it.
"The president's actions and his comments over the last 24 hours are the exact opposite of the intent of that bill," Tillis said, adding, "I will guarantee you at the first opportunity Putin has to embarrass or undermine President Trump, he will."
As Trump's poll numbers have cratered, congressional Republicans have increasingly distanced themselves from the president, on matters ranging from the conflict in Iran to the trade war with Canada.
The Senate's No. 2 Republican, John Barrasso of Wyoming, defended the diesel deal on Sunday, telling CBS' "Face the Nation" that Trump is focused on bringing costs down for consumers, ranchers, farmers and truckers.
"The president is balancing and has to make tough decisions," Barrasso said.
Canadian Prime Minister Mark Carney in a call on Sunday with Ukrainian President Volodymyr Zelenskiy made it clear that the US-Russia diesel deal "is in direct opposition to the efforts of Ukraine, Canada, and our allies to create peace and stability in Europe," his office said in a statement.
In a social media post on Sunday, Trump claimed that Ukraine and Russia had agreed to what he described as an "energy ceasefire" that would take effect immediately, but did not elaborate.
Zelenskiy said he was still waiting to see details of the deal.
"Ukraine supports the ceasefire, and it is important that Russia support it as well," Zelenskiy said in a post on the Telegram app.
But there was no word from Moscow on the announcement, which followed days of US pressure on Ukraine to halt its attacks on Russian oil refineries.