Iran has sent its response to a European Union proposal to revive the 2015 nuclear deal, state news agency IRNA reported, as the country"s chief adviser to negotiations tweeted that an agreement was closer than ever, but not yet done. IRNA reported that Iran returned the draft Vienna Agreement to the EU Tuesday, but the agency didn"t publish Iran"s response. On Twitter, Iran"s negotiating team adviser Mohammad Marandi said Iran had "expressed its concerns" about the draft, but the "remaining issues are not very difficult to resolve." "Those concerns are founded upon past US/EU violations. I can"t say that there will be a deal, but we"re closer than we"ve been before," Marandi wrote. The United States withdrew from the deal in 2018 under then-President Donald Trump. In the wake of the US withdrawal, Iran has increasingly violated the agreements it made under the deal and expanded its nuclear program. Iran has said any final deal should protect the rights of the country and guarantee the lifting of sanctions, which could free up tens of billions of dollars in oil and gas revenue and boost Iran"s struggling economy. Citing the position of the Iranian negotiating team, IRNA reported Tuesday that differences remain on three issues. In two of those issues, the US had "expressed its verbal flexibility," IRNA reported. The third issue relates to parties "guaranteeing the continuation" of the Joint Comprehensive Plan of Action (JCPA), according to IRNA. And that "depends on the realism of the United States to secure Iran"s opinion," IRNA reported, citing the negotiating team. The issues were discussed in detail on Monday during a special meeting of the National Security Council, IRNA reported. The European Union has not officially acknowledged that it has received Iran"s response. Earlier on Monday, Iran"s Foreign Minister Hossein Amir-Abdollahian said if the US showed a realistic and flexible reaction to Iran"s offer, they "would be at the point of agreement." Amir-Abdollahian said Tehran was ready to reach a conclusion through a foreign ministerial meeting and announce the final agreement if its views were accepted. "The upcoming days are important days," he said. Last week, a State Department spokesperson told CNN that the US was "ready to quickly conclude a deal on the basis of the EU"s proposals." — CNN