President Obama's campaign for Congress to hold off on new sanctions over Iran's nuclear program won a key endorsement on Thursday when the chairman of the U.S. Senate Banking Committee rejected tightening measures against Iran now.
Senator Tim Johnson, a Democrat, said he agrees with the Obama administration that such legislation could disrupt delicate negotiations seeking to curb Iran's nuclear program. The Banking Committee oversees sanctions legislation in the Senate.
Iran's foreign minister also has said a new sanctions law would kill the interim agreement reached in Geneva on November 24. In that agreement, Tehran agreed to limit uranium enrichment in return for an easing of international sanctions.
Diplomats are continuing negotiations with a goal of reaching a comprehensive final deal in six months.
"We should not do anything counterproductive that might shatter Western unity on this issue," Johnson said at a hearing.
"We should make sure that if the talks fail, it was Iran that caused their failure. We should not give Iran, the P5+1 countries or other nations a pretext to lay responsibility for their collapse on us," he said.
The so-called P5+1 are the six major powers who negotiated the November 24 interim deal on Iran's nuclear program - Britain, China, France, Germany, Russia and the United States.
Johnson also said he and Senator Mike Crapo, the top Republican on the banking committee, had negotiated a bill that could be put into effect if Iran does not comply with the Geneva agreement or negotiations collapse.
The Obama administration is eager to remind companies hoping for an opening to do business with Iran that sanctions that have crippled the country's economy remain in place.
"We are very actively dissuading international oil companies and others who think that now may be a time to test the waters in Iran," David S. Cohen, undersecretary for terrorism and financial intelligence for the Treasury Department, said at the hearing.
Treasury Secretary Jack Lew met recently with more than 100 bank chief executives and other business leaders to give that message, he said.
Before the hearing, the U.S. government on Thursday blacklisted a number of entities under sanctions aimed at Iran's nuclear program.