Iranian President Ebrahim Raisi said on Saturday that Tehran is serious in its nuclear talks with world powers in Vienna, adding that the US removing the sanctions imposed on Iran would show that it is serious as well. "The fact that we presented the text of Iran's proposal to the negotiating parties shows that we are serious in the talks, and if the other side is also serious about the removal of sanctions, we will achieve a good agreement," Raisi said, according to Reuters . Iran has gradually scaled back its compliance with the 2015 nuclear deal it signed with world powers in response to former US President Donald Trump’s withdrawal from the agreement in May of 2018. Nuclear talks between Iran and world powers formally resumed in Vienna on Thursday and ended within an hour, though Russia's envoy to the talks said the meeting was productive. On Saturday, Iran's top negotiator said that several issues remained unresolved in the Vienna talks. "Several points of difference have remained which require decision-making at the high-level and these are still on the table unresolved," said Ali Bagheri Kani, according to Reuters . Iran has repeatedly demanded that the US lift sanctions imposed on Iran and also reassure Iran it will not abandon the deal again as a precondition for its returning to compliance with the deal. US officials have said that while they prefer the diplomatic route to reach an agreement with Iran, there are other options on the table should that fail. White House Press Secretary Jen Psaki told reporters this week that the United States is preparing "additional measures" against Iran should the nuclear talks not succeed. "The president has asked his team to be prepared in the event that diplomacy fails and we must turn to other options," said Psaki. "We will have no choice but to take additional measures," she added. Related articles: 'Bad things' will happen to Iran without a deal Iran sends response to Trump on nuclear talks Iran open to indirect talks with US 'Iran has to give up its nuclear program'