A bipartisan group of six senators on Sunday called for President Donald Trump's administration to "immediately reverse course" on a plan to purchase diesel from Russia as part of an effort to lower high fuel prices.

Trump shocked lawmakers when he announced on social media Friday that he struck a deal with Russian President Vladimir Putin in a phone call.

He said Russia will immediately supply more than 300,000 tons of diesel to the American and global market, followed by an additional 500,000 tons in November and 1 million tons "immediately thereafter." Russia will deliver an additional 3 million tons "within a short period of time" after that, he wrote.