MANAMA, Bahrain — European efforts to persuade Iran to stick within the limits of the nuclear deal have been insufficient and the country will breach uranium stockpile limits “soon,” Tehran’s semiofficial Fars News Agency reported Saturday, a move that could further escalate tensions with the United States.

Iran has been threatening to surpass the limit of 300 kilograms (660 pounds) of low-enriched uranium that the country is allowed to possess under the nuclear agreement, unless it receives the sanctions relief that the deal promised in return. 

Breaching the limit would be a symbolic move but would not put Iran significantly closer to building a nuclear weapon. The 300-kilogram limit of uranium enriched to 3.67 percent is suitable for use in power plants but falls far short of the more than 90 percent enriched uranium needed for fissile material in a nuclear bomb.

The move would come against the backdrop of knife-edge tensions in the region, with President Trump last week saying he had been close to launching a strike on Iran after its forces shot down a U.S. surveillance drone in the Strait of Hormuz. The United States has also accused Iran of using magnetic limpet mines to attack petrochemical tankers in the Gulf of Oman — which Tehran denies. 

The U.S. Air Force said Friday that it had deployed its most advanced fighter jet, the F-22 Raptor, to the region for the first time to “defend American forces and interests.” It published pictures of the planes landing at Al Udeid Air Base in Qatar a day earlier.  

The United States last year pulled out of the Obama-era nuclear agreement between Tehran and six world powers. Trump, who describes the deal as “rotten,” has since reinstated all sanctions and introduced more, crippling Iran’s economy.

The remaining signatories have attempted to keep the deal alive. But Iran has said that it should no longer be constrained by the terms of the agreement, because it cannot reap any of the benefits as long as international firms worry about violating U.S. sanctions.

European countries say the deal is essential to regional security. Britain, France and Germany have scrambled to launch a complicated barter system in an effort to enable European companies to continue trading with Iran and persuade it to abide by the deal. After a meeting of the remaining signatories Friday in Vienna, the European Union announced that the barter system was operational. Iran had initially welcomed that move as a “positive step” that it would “study.” 

On Saturday, an unnamed “informed source” quoted by Fars indicated that the European system had fallen short. 

The effort “failed to meet our demands,” the official said. “Iran is determined to cut its commitments to the deal and the 300-kg enriched uranium limit will be soon breached.”

However, Iran’s official news agency, IRNA, did not carry similar statements. An article published by Tasnim, a news outlet close to Iranian hard-liners, questioned whether Iranian President Hassan Rouhani would “fall for the European lollipop again,” indicating that there may still be debate within the Islamic Republic on how to respond. 

There is “concern” that the Iranian government will fall for the “defective” move and backtrack from its ultimatum to reduce its commitments to the nuclear deal, the Tasnim article said.   

The barter system is limited in scope and aimed at allowing small- to medium-size businesses to continue trading with Iran, with a focus on essentials such as medicines and humanitarian goods, which are not subject to sanctions. 

However, Iran has argued that it should also be allowed to sell oil. 

Brian Hook, the U.S. special representative for Iran, told reporters Friday in London that any country purchasing Iranian oil would be subject to sanctions. 

Iran had previously threatened to breach the stockpile limits by Thursday, before appearing to wait for the results of Friday’s meeting in Vienna.