Dubai, Mar 12 (AP) Negotiations aimed at restoring Iran's tattered nuclear deal with world powers went on what its European hosts described as "a pause" on Friday, after Russia demanded relief from sanctions targeting Moscow over its war on Ukraine.

Diplomats offered no timetable for when the monthslong talks in Vienna would resume. Negotiators even on Friday maintained that a roadmap was near for how the United States could rejoin the accord it unilaterally withdrew from in 2018, and for Iran to again limit its rapidly advancing nuclear program.

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While Josep Borrell, the European Union's foreign policy chief, only referred to "external factors" forcing the pausing, it appeared the Russian demand caused the disruption.

"The real issue for this pause here is what Russia has thrown on the table, which is essentially a grenade in the middle of the negotiations," said Henry Rome, deputy head of research at the Eurasia Group who has been following the talks.

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Last week, Russian Foreign Minister Sergey Lavrov said he wanted "guarantees at least at the level of the secretary of state" that the US sanctions would not affect Moscow's relationship with Tehran.

While American officials sought to describe the demand as not related to the Vienna talks, matters swiftly stalled Friday with a tweet from Borrell.

"A pause in (hashtag) ViennaTalks is needed, due to external factors. A final text is essentially ready and on the table," Borrell wrote. "As coordinator, I will, with my team, continue to be in touch with all (hashtag)JCPOA participants and the U.S. to overcome the current situation and to close the agreement."

The JCPOA, or the Joint Comprehensive Plan of Action, is the formal name of the 2015 deal that saw Iran limit its uranium enrichment in exchange for the lifting of economic sanctions.

EU negotiator Enrique Mora met Friday with Iranian officials before telling journalists that "we are almost there" with the talks.

"Almost everything is done," Mora said. "We are almost at the limit of negotiating footnotes."

Iranian Foreign Ministry spokesperson Saeed Khatibzadeh said the pause "could be a momentum for resolving any remaining issue" ahead of restoring the deal.

"Successful conclusion of talks will be the main focus of all,” he wrote on Twitter. "No external factor will affect our joint will to go forward for a collective agreement."

Khatibzadeh did not identify the "external" issue — Iran has been careful in the waning days of the talks not to upset Russia, which it views as an ally against the US.

Iran also partnered with Russia in Syria to support Syrian President Bashar Assad. But historic distrust between the nations remains over Russia's invasion of Iran during World War II and refusing to leave afterward.

A report by Iran's state-run IRNA news agency, quoting an anonymous source it described as close to Tehran's negotiators, also suggested Russia's demands caused the pause.

"There are some issues such as the issues between Russia and the United States, which, of course, will be unrelated to the issue of Iran's talks … and that need to be resolved between the US and Russia," IRNA quoted the source as saying.

However, Russian Ambassador Mikhail Ulyanov, speaking to journalists outside of the Vienna hotel where the talks took place, insisted: "I'm not aware of any impasse." "Contacts will continue," he said. "The conclusion of the deal does not depend on Russia only."

Chinese Ambassador Wang Qun said negotiators "regret the pause" and added, "as we know, negotiation cannot be conducted in a political vacuum.”

German Chancellor Olaf Scholz said it was key for the negotiation that there are "no attempts from outside to undo the success of these talks."

"For me it is very clear that it is also the job of powers such as Russia or China that they support these results constructively," Scholz said.

In Washington, US State Department spokesman Ned Price said Friday that negotiators are "still working through a number, a very small number, but still a number of what are undoubtedly difficult issues."

But he also warned America had "no intention of offering Russia anything new or specific as it relates to the (Ukraine) sanctions."

"There will need to be decisions made in places like Tehran and Moscow," Price told reporters. "And if that political will is there, if that seriousness of purpose is there, we remain confident that we can achieve a mutual return to compliance in fairly short order.”

However, British negotiator Stephanie Al-Qaq struck a more somber note, warning Friday on Twitter that the "external factors must be resolved in next few days or agreement likely to unravel." The 2015 nuclear deal saw Iran put advanced centrifuges into storage under the watch of the International Atomic Energy Agency, while keeping its enrichment at 3.67% purity and its stockpile at only 300 kilograms (661 pounds) of uranium. It also halted enrichment at its underground Fordo nuclear facility.

As of Feb. 19, the IAEA says Iran's stockpile of all enriched uranium was nearly 3,200 kilograms (7,055 pounds). Some has been enriched up to 60% purity — a short technical step from weapons-grade levels of 90%. Meanwhile, Iran has stopped the IAEA from accessing its surveillance camera footage and has resumed enrichment at Fordo.

That has worried nuclear nonproliferation experts. While Iran insists its program is peaceful, the IAEA and Western governments say Iran had an organized military nuclear program up until the end of 2003. (AP)

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