The United States Senate has voted 98-2 to impose new sanctions on Russia, Iran and North Korea, despite objections from the White House.
The House of Representatives approved the bill earlier this week, also by an overwhelming majority.
Having passed through both chambers, it will be sent to President Trump to sign into law.
But Mr Trump has sought closer ties with Russia, and has the power to veto the bill despite its political support.
A presidential veto can, in turn, be overridden by a two-thirds vote in the House and Senate - where just a handful of politicians voted against the bill.
Where does Mr Trump stand?
The sanctions were drawn up in part to punish Russia further over the annexation of Crimea from Ukraine in 2014.
But the debate over the new measures has taken place against the backdrop of an ongoing investigation into alleged Russian meddling the in the 2016 presidential election.
Mr Trump has repeatedly denied the existence of any Russian involvement in the election to help his campaign.
But political correspondents say an attempt to veto the new sanctions could fuel suspicion that he is too supportive of the Kremlin.
The White House is also said to be particularly concerned over a provision in the new bill which would limit President Trump's ability to lift the sanctions.
Under the legislation, he would be forced to consult Congress first.
Speaking earlier this week after the House passed the bill, top-ranking Republican Paul Ryan said it "tightens the screws on our most dangerous adversaries in order to keep Americans safe".
But the bill was criticised by some European countries which deal with Russian energy pipelines - which may fall foul of the new sanctions.
What happens next?
It remains to be seen if the president will attempt to veto the bill.
New White House Communications director Anthony Scaramucci told CNN: "He may sign the sanctions exactly the way they are or he may veto the sanctions and negotiate an even tougher deal against the Russians."
Earlier this week, the White House simply said it was reviewing the bill, "and awaits a final legislative package for the president's desk".
What about Iran and North Korea?
While much of the attention is on the Russia sanctions, both Iran and North Korea are facing increased pressure over their missile programmes.
The sanctions will target financial organisations that deal with North Korea, as well as any person or business involved with Iran's missile programme or its Islamic Revolutionary Guards Corps.
Hours later, Japan said it would also impose additional sanctions on North Korea. Kyodo news agency reported that the new measures would, for the first time, target the assets of people and organisations not directly linked to the missile programme - including foreign financial organisations.