Despite the contradictory messaging from the US and Iran, there appears to be real momentum toward a deal, says international security professor Stefan Wolff.

US President Donald Trump flagged progress in talks with Iran, Tehran has warned that major gaps still stand in the way of dialing down the conflict.

Trump also warned that if the US and Iran do not come to an agreement, "we're going to have a situation where no country will ever be hit as hard as they're about to be hit."