The Iran nuclear talks are likely to miss Tuesday’s deadline for a comprehensive agreement. Foreign Minister Javad Zarif has returned to Iran to discuss a final negotiation position with the country’s top leadership. Ahead of Zarif’s departure, Secretary of State John Kerry acknowledged gaps remain.

Secretary of State John Kerry: “I think it’s fair to say that we’re hopeful. We have a lot of hard work to do. There are some very tough issues. And I think we all look forward to getting down to the final effort here to see whether or not a deal is possible. I think everybody would like to see an agreement, but we have to work through some difficult issues.”

The outstanding differences include access to international inspectors and Iranian nuclear activity in the deal’s final years.