Seven U.S. senators from both parties urged President Donald Trump to abandon the agreement allowing Russia to increase diesel supplies.
Four Republicans and three Democrats joined the appeal.
The lawmakers said the deal could conflict with U.S. restrictions on Russian energy imports imposed after Russia’s full-scale invasion of Ukraine.
They also asked the administration to explain the legal basis for temporarily easing the restrictions.
More senators later joined the opposition to the deal, but as of October 11 the initiative had seven signatories.