Delegations from the United States and Iran on Saturday resumed "indirect" negotiations on a nuclear deal in Rome, with another round of talks set for next Saturday, after experts hash out technical matters Wednesday.

US and Iranian delegations will gather in Rome Saturday for a second round of high-level talks on Tehran’s nuclear program amid tempered optimism about a diplomatic way forward.

Iran and the United States started a new round of nuclear talks in Rome on Saturday to resolve their decades-long standoff over Tehran's atomic aims, under the shadow of President Donald Trump's threat to unleash military action if diplomacy fails.