Mr. Trump’s chief envoy to the talks, Steve Witkoff, has also sent mixed signals over what the United States wants. Over the past week, he has moved from suggesting Iran could have a limited nuclear program to saying Iran needed to fully dismantle it.

The United States and Iran are due to hold their second round of nuclear talks on Saturday, as what both sides are looking for in a deal begins to take shape.

Oman's Sultan Haitham bin Tariq al-Said is set to visit Moscow on Monday, days after the start of a round of Muscat-mediated nuclear talks between the U.S. and Iran.

ROME—Iran is planning to set out a series of proposals for a new nuclear pact, including guarantees from the Trump administration that the U.S. won’t leave a future accord, people familiar with the matter said,

Iran told the United States in talks last week it was ready to accept some limits on its uranium enrichment but needed watertight guarantees President Donald Trump would not again ditch a nuclear pact,

US President Donald Trump has refused to support Israel in a potential attack on nuclear facilities in Iran, the New York Times reported, citing unnamed US government officials. Instead, Trump advocated for negotiations with Tehran,