The new sanctions fit into U.S. President Donald Trump's effort to limit Iran's regional influence and come a week after U.S.-brokered deals for the United Arab Emirates and Bahrain to normalize ties with Israel.

The United States faces defeat in its move to reimpose U.N. sanctions on Tehran, Iranian President Hassan Rouhani said in a televised speech on Sunday, as Washington declared all U.N. sanctions on Iran had been restored.

Helga Schmid, the European Union representative who chaired the meeting, said afterwards on Twitter that the "participants are united in resolve to preserve the #IranDeal and find a way to ensure full implementation of the agreement despite current challenges."

International Atomic Energy Agency Director General Mariano Grossi told reporters after a meeting of the agency's board in Vienna that he had made his case with "Iranian authorities at higher levels."

"Iran will never negotiate under pressure ... We will never yield to America's pressure and we will not negotiate from a position of weakness," Rouhani said in a televised news conference.

Iran's Iran's clerical rulers face challenges in keeping the economy afloat under increasingly tough U.S. sanctions imposed by Washington after it withdrew in from Tehran's nuclear deal with world powers.

Iran is not ruling out negotiations with the United States even after an American drone strike that killed a top Iranian general, the country's foreign minister said in an interview released Saturday.

The European Union's top diplomat said Friday that more time is required to unravel a dispute between countries involved in the Iran nuclear agreement.

Rouhani said Iran remained committed to the deal and could reverse its steps away from compliance if other parties fulfilled their obligations.

The Islamic Republic has been reeling from one crisis to another. Here's a closer look.