Associated Press
In this picture released by an official website of the office of the Iranian supreme leader on Wednesday, May 20, 2015, Supreme Leader Ayatollah Ali Khamenei, right, arrives at a graduation ceremony of the Revolutionary Guard's officers, while deputy commander of the Revolutionary Guard, Hossein Salami, second right, former commanders of the Revolutionary Guard Mohsen Rezaei, second left, and Yahya Rahim Safavi salute him in Tehran, Iran.

WASHINGTON — The top U.S. and Iranian diplomats plan to meet this weekend in Switzerland as efforts intensify to reach a comprehensive nuclear accord.

Secretary of State John Kerry and Iranian Foreign Minister Mohammad Javad Zarif will hold talks Saturday in Geneva.

State Department spokesman Jeff Rathke says the goal is to make progress toward an agreement by an end of June deadline.

European and Iranian officials have suggested the talks may require more time. But Rathke says the U.S. isn't considering an extension.

Kerry leaves Washington on Thursday for Nigeria, where he'll attend Muhammadu Buhari's presidential inauguration.

From Geneva, Kerry will head to Madrid to meet with Spain's king and prime minister. Later, Kerry will attend a conference in Paris on fighting the Islamic State group.