Rubio did not confirm a meeting on Friday with Iran's clerical state, which has violently put down some of the most serious protests against its rule since the 1979 Islamic revolution.

"If the Iranians want to meet, we're ready," Rubio told reporters.

"They've expressed an interest in meeting and talking. If they change their mind, we're fine with that too," he said, after President Donald Trump ordered a sharp military buildup near Iran's coast and threatened to strike.

"In order for talks to actually lead to something meaningful, they will have to include certain things, and that includes the range of their ballistic missiles, that includes their sponsorship of terrorist organizations across the region, that includes their nuclear program and that includes the treatment of their own people," Rubio said.

Iran in previous talks on its disputed nuclear program has ruled out discussions on its missiles, casting the weapons that can hit Israel as a tool of self-defense to which every country has a right.

But Iran has been under growing pressure from the protests and after an Israeli bombing campaign last year. Iran has also lost key regional allies with Israel's severe degrading of Lebanon's Hezbollah and the fall of veteran Syrian president Bashar al-Assad.

Iranian state media said Wednesday that talks with the United States would take place Friday in Oman, after diplomats earlier said the meeting would happen on Friday in Turkey.

Rubio said that US envoy Steve Witkoff had been ready to meet with Iran in Turkey but then received "conflicting reports" on whether Tehran had agreed.

"That's still being worked out," he said of the location for the talks.