By Patricia Zengerle
WASHINGTON (Reuters) - The U.S. Senate passed a 10-year extension of sanctions against Iran on Thursday, sending the measure to the White House for President Barack Obama to sign into law and delaying any potentially tougher actions until next year.
The measure passed by 99-0. It passed the House of Representatives nearly unanimously in November, and congressional aides said they expected Obama would sign it.
The ISA will expire on Dec. 31 if not renewed. The White House had not pushed for an extension, but had not raised serious objections.
Members of Congress and administration officials said the renewal of the Iran Sanctions Act (ISA) would not violate the nuclear agreement with Iran reached last year.
"While we do not think that an extension of ISA is necessary, we do not believe that a clean extension would be a violation of the JCPOA (Iran deal)," a senior administration official said.
Iranian Supreme Leader Ayatollah Khamenei said recently the extension would breach the agreement and threatened retaliation.
Democrats who backed the accord said they did not believe the ISA extension violated the pact because it continued a sanctions regime that was already in place. They said they had not heard such objections from U.S. partners.
"I have not heard strident objections from our key allies in the JCPOA," Democratic Senator Chris Coons told reporters.
The agreement was signed by the United States, Britain, Russia, France, China, Germany and Iran.
Congress' action did not address the fate of the nuclear pact, which was opposed by every Republican in the Senate and House. Lawmakers said it would make it easier for sanctions to be quickly reimposed if Iran violated the deal.
Republican U.S. President-elect Donald Trump railed against the pact as he campaigned for the White House. Many other members of his party, which also controls Congress, have called for the new administration to tear up the agreement.
Senate Foreign Relations Committee Chairman Bob Corker said the renewal ensures Trump can reimpose sanctions Obama lifted under the deal, in which Iran curbed its nuclear program in exchange for sanctions relief.
"Extending the Iran Sanctions Act ... ensures President-elect Trump and his administration have the tools necessary to push back against the regime’s hostile actions," Corker said in a statement.
Trump becomes president on Jan. 20. Corker has been mentioned as a possible Trump secretary of state.
(Fixes typo in word "objections" in paragraph 8.)
(Additional reporting by Roberta Rampton; Editing by Andrew Hay and James Dalgleish)