Little progress has been made in talks between Iran and six world powers on overcoming difficulties over Tehran’s nuclear programme.
Officials on both sides at the UN in New York say differences remain serious ahead of an end-of-November deadline.
The Iranian President Hassan Rohani, hoping for a deal to end sanctions against his country, says progress has been “extremely slow”.
“Iran will never surrender its legal right to the pursuit of civil peaceful nuclear activity. The (uranium) enrichment will continue under this framework in Iran,” Rohani told a news conference.
“Any agreement with Iran in which the right is not officially recognised of continuing enrichment on Iranian soil will not be accepted as legitimate by us,” he added. “The sanctions must completely melt away and be deactivated.”
Western powers want to ensure Iran is not hiding a military nuclear programme.
The US Secretary of State John Kerry says last November’s interim deal under which Iran halted high-level enrichment in exchange for limited sanctions relief has “made the world safer”.
Officials had warned before the latest negotiations that a breakthrough was unlikely, but were still hoping for more progress.
More talks are expected soon but no date or venue has been set.