Talks are underway in high-level negotiations to limit Iran’s nuclear program in exchange for easing crippling sanctions on the Islamic republic’s economy.

Facing a Nov. 24 deadline before negotiations expire, U.S. Secretary of State John Kerry met Sunday with Iranian Foreign Minister Javad Zarif and European Union adviser Catherine Ashton.

Kerry has said real gaps between Tehran and world powers still exist in the negotiations. But the U.S. remains hopeful a deal can be brokered in what would mark a major foreign policy success for the Obama administration.

The three diplomats did not make any comments to journalists at a brief photo opportunity as the negotiations began.

Negotiators from Britain, China, France, Germany and Russia are expected to join the final round of talks starting Nov. 18 in Vienna.

(AP)