Russian Foreign Minister Sergey Lavrov (SEHR'-gay LAHV'-rahf) will travel to Vienna to join Iran nuclear talks. He will meet there with U.S. Secretary of State John Kerry in an attempt to resolve disputes that have forced an extension of the negotiations past the June 30 deadline.

Lavrov is to arrive Tuesday, the day that Iranian Foreign Minister Mohammad Javad Zarif returns to Vienna.

As Zarif flew home Sunday for consultations on how to proceed at the talks, a U.S. official confirmed that negotiators will miss a June 30 target date for a deal, aimed at limiting Tehran's nuclear program in exchange for sanctions relief.

Russian news agencies cited Lavrov as saying he and Kerry will also discuss pooling Russian and U.S. efforts to fight Islamic State.