WASHINGTON -- Talks have resumed in Geneva between American and Iranian diplomats, after the parties extended negotiations over Iran's nuclear program for the second time in a year.On Monday, Iranian officials expressed optimism that the third time might be the charm.Monday's session, the first to take place in the overtime period, "lasted more than six hours and proceeded in a good ambience," said Iranian chief negotiator and deputy foreign minister Abbas Araghchi. "At present, issues have boiled down to very minor, fine details."Iranian President Hassan Rouhani also pledged on Monday to overcome hardline opposition at home to virtually any agreement with the West. Those to his right refuse to entertain any dismantlement of the nuclear program, and instead want to expand it.Aiming to seal a political agreement ending concerns over the nuclear program by late March, and a comprehensive agreement by June, Western diplomats agreed to extend the talks citing substantial progress on "once-intractable" issues within the negotiations.Any final agreement will require the approval of Iran's supreme leader, Ayatollah Ali Hosseini Khamenei. "There is yet some distance to a solution," Araghchi added.Reuters contributed to this report.