Top negotiators in renewed talks to revive the 2015 Iran nuclear deal said they were optimistic about the possibility of a deal to impose limits on Tehran’s uranium enrichment. “We are five minutes or five seconds from the finish line,” Russian Ambassador Mikhail Ulyanov told reporters outside Vienna’s Palais Coburg on Sunday, four days after the talks. He said there were “three or four issues” that needed to be resolved. “They are sensitive, especially to the Iranians and the Americans,” Ulyanov said. “I can’t guarantee, but the impression is that we are moving in the right direction.” Enrique Mora, the European Union’s top negotiator, also said he was “absolutely” optimistic about the progress of the talks so far. “We are moving forward and I expect we will close the negotiations soon,” he told Iranian media. Negotiators from Iran, the United States and the EU restarted indirect talks on Tehran’s scrappy nuclear deal on Thursday after a months-long deadlock in negotiations. Hours after the US imposed a fresh batch of sanctions targeting Iran’s petrochemical exports, Tehran responded by ordering gas to power “hundreds” of advanced centrifuges, further accelerating its nuclear program. Iran closed the nuclear deal in 2015 with the US, France, Germany, Britain, Russia and China. The deal saw Iran agree to curb uranium enrichment under the watch of United Nations inspectors in exchange for the lifting of economic sanctions. US President Donald Trump then unilaterally withdrew the US from the deal in 2018, saying a stronger deal would be negotiated, but that did not happen. Iran began violating the terms of the deal a year later.