The US Senate approved a 10-year extension of sanctions against Iran, a bipartisan measure that would have expired at year's end but now goes to President Barack Obama's desk.
The Iran Sanctions Act passed the Senate 99-0, after easily clearing the House of Representatives in November.
Obama is expected to sign the measure, a White House official said, adding that the administration does not believe the extension violates the nuclear agreement that was reached last year with Iran.
The legislation does not directly address the nuclear pact. But some say the restrictions in the bill go against the spirit of the agreement, under which Tehran curbed its nuclear program in exchange for sanctions relief from the United States and other nations.
Senate Democrats Dianne Feinstein and Tim Kaine, who both backed the Joint Comprehensive Plan of Action with Iran, said that while the president is currently waiving some sanctions as part of the agreement, "sanctions legislation must remain in place to allow an immediate 'snap-back' should Iran violate the JCPOA."
The extension signals congressional commitment to vigorously enforce the pact, and would "make clear that there will be immediate consequences should Iran break the terms of the agreement, including the re-imposition of sanctions," they said.
The bill includes penalties against Iran's banking sector, as well as its energy and defense industries.
Last month, Iran's supreme leader Ayatollah Ali Khamenei warned that the Islamic republic would "react against" the new sanctions extension if it becomes law.
US President-elect Donald Trump heavily criticized the pact as he campaigned for the White House over the past year. Several fellow Republicans remain vehemently opposed to the nuclear deal and have called for its termination.
Extending the sanctions "ensures President-elect Trump and his administration have the tools necessary to push back against the regime's hostile actions," said Senate Foreign Relations Committee chairman Bob Corker, who Trump has been considering as a possible pick for secretary of state.