(Adds more detail from letter)
WASHINGTON, Jan 26 (Reuters) - U.S. business groups warned the White House on Tuesday that congressional plans to expand U.S. sanctions on Iran threaten to significantly undermine U.S. economic and security interests.
"The proposed sanctions would incite economic, diplomatic, and legal conflicts with U.S. allies and could frustrate joint action against Iran," the U.S. Chamber of Commerce and other business groups said in a letter to top White House officials.
Senate Majority Leader Harry Reid said earlier on Tuesday that he hoped the Senate would pass legislation within the next few weeks authorizing sanctions on companies that provide gasoline to Iran.
"The act will create new pressure on the Iranian regime to help stop Iran from acquiring a nuclear weapon," Reid said on the Senate floor. "I am reaching out to Republican colleagues to help me find a path to get that done in the next few weeks weeks."
The House of Representatives passed a similar sanctions bill in December.
The business groups told White House national security adviser James Jones and senior economic policy adviser Lawrence Summers they agreed with the goal of stopping Iran from developing a nuclear bomb.
But they expressed concern about provisions of the House and Senate bills that "could prohibit any U.S. company from transacting routine business with critical partners from around the globe, even if these transactions have no bearing on business with Iran."
"These provisions could encompass a very large portion of the global trade community, with consequences that in our view have not been adequately assessed," the groups said.
They warned the proposals could have a large impact on the U.S. Export-Import Bank by preventing it from working with foreign counterparts to help finance U.S. exports that have no relation to Iran's energy sector.
"We urge you to weigh in vigorously with Congress to eliminate these highly problematic proposals," the groups told the top White House officials.
Other groups that signed the letter included the Business Roundtable, the Emergency Committee for American Trade, the National Association of Manufacturers, the National Foreign Trade Council and the U.S. Council for International Business.
(Reporting by Doug Palmer and Susan Cornwell; Editing by Sandra Maler)