Trump on Tuesday recast the Russian diesel plan as "a deal for the world," backing away from last week's boast after criticism spread through both parties.
13.5 million barrels are slated for release in phases, and the administration has already authorized US purchases of Russian diesel through next April.
Seven senators — including four Republicans — urged Trump to "immediately reverse course," while some GOP candidates have distanced themselves from the plan on the campaign trail.
Diesel prices offered little support for the move: the US average edged up to $6.28 a gallon Tuesday, and analysts said wholesale markets were "not blinking" and truckers and farmers would see no near-term relief.
The backlash has widened because experts question whether the imports are legal or feasible and critics say the purchases could help finance Russia's war in Ukraine.