Iran has increasingly complained about these non-nuclear sanctions, particularly the prohibition on Iranian access to the American financial system and use of the dollar. The Iranians say such restrictions have discouraged many foreign companies from investing in Iran, subverting the economic rewards it expected from the nuclear agreement.

Republicans and many Democrats opposed the agreement, asserting that Iran was untrustworthy and had gained too many concessions during the negotiations.

President-elect Donald J. Trump said during his campaign that he would renegotiate the accord or renounce it. In a March speech to the American Israel Public Affairs Committee, the most powerful pro-Israel lobby group in Washington, he said his top priority was to “dismantle the disastrous deal with Iran.”

Whether he will follow through on that pledge remains unclear. The other countries that agreed to the deal with Iran — Britain, China, France, Germany and Russia — have said they intend to honor it. President François Hollande of France said on Tuesday that he did not believe Mr. Trump would scrap the agreement, telling the France 24 television channel that the “absence of an accord would be very serious.”