A second round of nuclear talks between the United States and Iran concluded on Saturday, with both sides indicating progress.

Delegations from both countries met in Rome for negotiations following an initial round in Oman last weekend. The Gulf Arab nation has mediated both rounds of the indirect talks, including an upcoming third high-level round expected in Oman on Saturday.

The Trump administration expressed optimism following the latest talks, pointing to “very good progress” and saying the parties had “agreed to meet again” next week. “Today, in Rome, over four hours in our second round of talks, we made very good progress in our direct and indirect discussions,” a senior administration official told CNN.

Iranian Foreign Minister Abbas Araghchi also signalled that the talks had been positive. “I can say that there is movement forward. We’ve reached better understanding and agreement on some principles and goals in these Rome negotiations,” he said.

President Donald Trump has threatened that the US will resort to military strikes against Iranian nuclear sites, with Israel’s help, should Tehran fail to reach a deal with its interlocutors.

Members of the Trump administration have flip-flopped in remarks over the past week, oscillating between maximalist demands that Iran has said were “red lines” and a more conciliatory approach.