Mr Zarif is in Vienna for talks with US Secretary of State John Kerry over Iran's nuclear deal.

The international nuclear watchdog, the IAEA, is expected to confirm that Iran has scaled back its atomic activities in line with the agreement.

Lifting sanctions would unfreeze billions of dollars of assets and allow Iranian oil to be sold internationally.

Iran nuclear deal: Key details

"Today is a good day for the Iranian people as sanctions will be lifted today," Iran's ISNA agency quoted Mr Zarif as saying.

He said the IAEA's report meant implementation of the nuclear deal would go ahead.

The State Department said all parties had "continued making steady progress" towards implementing the deal, adding it would ensure the "exclusively peaceful nature" of Iran's programme.

As part of the deal, Iran had to drastically reduce its number of centrifuges and dismantle a heavy-water reactor near the town of Arak, both of which could be used in creating nuclear weapons. Iran has always maintained its programme is peaceful.