MANAMA, Bahrain — The U.S. special representative for Iran said Friday that Europe has a choice: Do business with the United States, or do business with Iran.

The comments by Brian Hook came as European countries made a last-ditch effort to prevent Iran from breaching the terms of a 2015 nuclear deal, a move that could add to soaring tensions in the Persian Gulf.

Europe has been scrambling to come up with a mechanism that will persuade Iran to stay within the limits of the deal, as Tehran complains that U.S. sanctions mean that it no longer sees the economic benefit of the accord.

Hook said sanctions on Iran would continue until it decides to be a “normal” state, Reuters news agency reported.

Iran has indicated that if it does not receive some form of sanctions relief, it plans to exceed a limit of 300 kilograms (660 pounds) of low-enriched uranium that the country is allowed to possess under the nuclear agreement.

The potential for a breach adds urgency to a meeting Friday of officials from Iran, Britain, France, Germany, Russia, China and the European Union, a meeting that takes place every quarter to discuss the implementation of the deal.

Three of the parties — Britain, France and Germany — have been attempting to set up a barter system that would allow some trade to continue with Iran and keep it from breaching the deal. But the Trump administration has been critical of the program, which it sees as an attempt to evade its sanctions, while Iran has been skeptical that the system can get off the ground.

If the European barter system, known as Instex, fails to “meet Iran’s demands within the framework for the nuclear deal,” then Iran will “take the next steps more decisively,” Iranian Foreign Ministry spokesman Abbas Mousavi told state television on Friday.

President Trump last year pulled out of the Iranian nuclear deal, officially called the Joint Comprehensive Plan of Action (JCPOA), which curbed Iran’s nuclear activities in return for the lifting of sanctions. He had repeatedly denounced the deal reached during the Obama administration between Iran and six world powers, including the United States, calling it “rotten,” and he reimposed U.S. sanctions that had been lifted as part of the pact.

A new round of U.S. sanctions, targeting Iran’s supreme leader, Ayatollah Ali Khamenei, and other senior Iranian officials, was announced by Washington on Monday after attacks on tankers in the Gulf of Oman and the shooting down of a U.S. surveillance drone over the Strait of Hormuz. The United States has blamed tanker attacks on Iran, which has denied involvement.

Trump has said the downing of the U.S. Navy drone, which Iran said it hit with a surface-to-air missile, almost caused him to order a military strike against Iran. Trump said he called it off at the last minute because it would have inflicted disproportionate Iranian casualties.

U.S. officials have indicated that they would like to see Iran abide by the terms of the nuclear deal, even though the United States withdrew from it. “Our sanctions do not give Iran the right to accelerate its nuclear program,” Hook said before a meeting in Paris on Thursday. “It can never get near a nuclear bomb.”

An Iranian breach of the stockpile limit would not put it significantly closer to building a nuclear weapon, but it would strike another blow to the tattered deal. The stockpile of uranium enriched to 3.67 percent is suitable for use as fuel in nuclear power plants but far short of the weapons-grade level of more than 90 percent needed for fissile material in a nuclear bomb.

On Thursday, Iranian media reported that Foreign Minister Mohammad Javad Zarif sent a letter to European Union foreign policy chief Federica Mogherini urging European signatories to stick by their commitments under the deal, with Iran’s next steps depending on that.