DUBAI, UNITED ARAB EMIRATES -- Indirect negotiations between Iran and the U.S. over Tehran's tattered nuclear deal with world powers ended Wednesday in Qatar after failing to make significant progress amid a growing crisis over the Islamic Republic's atomic program, diplomats said.

The Doha talks broke up after two days without any sign of a breakthrough, months after talks in Vienna among all of the deal's parties went on 鈥減ause." In the time since, Iran shut off surveillance cameras of international inspectors and now has enough high-enriched uranium to potentially fashion into at least one nuclear bomb if it chose.

And with Iran and the U.S. blaming each other for the talks' failure, it remains unclear when 鈥 or if 鈥 there will be another round of negotiations.

European Union mediator Enrique Mora on Twitter described as 鈥渋ntense鈥 the two days of talks in Doha.

"Unfortunately, not yet the progress the EU team as coordinator had hoped-for," Mora wrote. 鈥淲e will keep working with even greater urgency to bring back on track a key deal for non-proliferation and regional stability.鈥

Mora's comments came hours after the semiofficial Tasnim news agency, believed to be close to Iran鈥檚 hard-line Revolutionary Guard, described the negotiations as finished hours before they ended and having 鈥渘o effect on breaking the deadlock in the talks.鈥

Tasnim claimed that the American position did not include 鈥渁 guarantee for Iran benefiting economically from the deal,鈥 quoting what it described as unnamed 鈥渋nformed sources.鈥

鈥淲ashington is seeking to revive the (deal) in order to limit Iran without economic achievement for our country,鈥 the Tasnim report claimed. A key sticking point has been American sanctions targeting the Guard.

U.S. Special Representative Rob Malley spoke to the Iranians through Mora during the talks. Mora then took messages to Iran鈥檚 top nuclear negotiator Ali Bagheri Kani.

After the Tasnim report, Foreign Minister spokesman Nasser Kanaani issued a statement describing the talks as 鈥渂eing held in a professional and serious atmosphere.鈥 He later said that Iran and Mora 鈥渨ill be in touch regarding the continuation of the route and the next stage of the talks.鈥

However, it remains unclear if there will be another round of talks on the deal, known formally as the Joint Comprehensive Plan of Action. The State Department said that Iran "raised issues wholly unrelated to the JCPOA and apparently is not ready to make a fundamental decision on whether it wants to revive the deal or bury it.鈥

鈥淚ndirect discussions in Doha have concluded, and while we are very grateful to the EU for its efforts, we are disappointed that Iran has, yet again, failed to respond positively to the EU鈥檚 initiative and therefore that no progress was made," the State Department said.

Iran and world powers agreed in 2015 to the nuclear deal, which saw Tehran drastically limit its enrichment of uranium in exchange for the lifting of economic sanctions. In 2018, then-President Donald Trump unilaterally withdrew America from the accord, raising tensions across the wider Middle East and sparking a series of attacks and incidents.

Talks in Vienna about reviving the deal have been on a 鈥減ause鈥 since March. Since the deal鈥檚 collapse, Iran has been running advanced centrifuges and rapidly growing stockpiles of enriched uranium. However, Tehran continues to suffer under intense economic sanctions while the West hopes to again curtail Iran's nuclear program.

鈥淭he incentive for Washington and Tehran to keep the prospect of a deal alive is strong, even as the actual likelihood of achieving a compromise diminishes,鈥 said Henry Rome, an analyst with the Eurasia Group tracking the negotiations. 鈥淔or that reason, we would expect the sides to resume talks in Doha in the near future, although we are not optimistic about a breakthrough.鈥