The Republican-controlled US Senate passed a legislative measure on Tuesday aimed at stopping American military operations against Iran, Reuters reported.
The direct impact on the ground remains uncertain as President Donald Trump's administration actively works to hammer out a peace accord with Tehran.
The concurrent resolution cleared the chamber in a tight 50-48 vote, following its approval by the House of Representatives earlier in the month.
The final tally fell mostly along party lines, though four Republicans crossed the aisle to vote alongside almost every Democrat. Two Republican senators sat out the vote entirely.
The approved text orders the president to withdraw American troops from active hostilities involving Iran, though the mandate is expected to function as a primarily symbolic gesture.
Because the measure was filed under the 1973 War Powers Act, it bypasses the executive branch and will not land on Trump's desk for an official signature.
For its part, the White House has already countered the move, arguing that the legislation is unconstitutional and holds no legal authority over the administration.