The United States and Iran have stuck to directly opposing stances over the Middle East country's uranium stockpile and controls on the Strait of Hormuz, although Secretary of State Marco Rubio says there have been "some good signs" in talks.
Speaking before departing for a NATO meeting, Rubio said there were "some good signs" in Pakistan-mediated negotiations. However, he added that he did not want to be "overly optimistic."
Rubio also repeated the US assessment that Iran's leadership system was "itself is a little fractured" and stressed that US President Donald Trump preferred a negotiated settlement.