US, Iran 'made very good progress' in talks: US official

"We agreed to meet again next week and are grateful to our Omani partners for facilitating these talks and to our Italian partners for hosting us today," the official said in a statement.

The official said the second round of talks in Rome lasted more than four hours.

Iranian Foreign Minister Abbas Araghchi described the talks as “constructive and good.”

Before the next round, Araghchi said there would be expert-level technical discussions between the two sides in Oman starting this Wednesday.

The indirect nuclear talks, which began last Saturday in Muscat, have been focused on Iran’s nuclear program, with the two sides communicating through Oman as an intermediary.

US President Donald Trump has threatened military action against Iran if a new agreement is not reached to replace the 2015 nuclear deal brokered under the Obama administration.