UNITED NATIONS (AP) — With little more than two months to deadline, Iran and six world powers on Friday launched a fresh effort at narrowing stubborn differences on what nuclear concessions Tehran must agree to in exchange for full sanctions relief.

The talks once again bring Iran to the negotiating table with the United States, Russia, China, Britain, France and Germany. But this time they are taking place on the sidelines of the U.N. General Assembly. That means U.S. Secretary of State John Kerry and his counterparts will likely join in, adding their diplomatic muscle to the meeting.