The White House has received a bill that would ramp up sanctions against Russia, which President Donald Trump must now sign into law or veto.
The sanctions bill was received by the White House at 1:53 pm (1753 GMT), a US government source told AFP.
Trump has given no firm indication about whether he will sign the bipartisan measure.
The bill — which also includes measures targeting North Korea and Iran — is designed to restrict Trump’s ability to lift punitive measures on Moscow.
Trump now faces a choice between swallowing a bill he deeply opposed and refusing to do so — a move that would intensify suspicions about his attitude to Russia.
He could outright veto — which would likely bring a humiliating veto override — or could, if Congress adjourns, issue a “pocket veto” by not signing the legislation within ten working days.