Six global powers will discuss ways to reach a comprehensive nuclear deal with Iran on the sidelines of the U.N. General Assembly in New York in September, the European Union's foreign policy chief said on Saturday.

Talks aimed at curbing Iran's nuclear program in exchange for ending sanctions began in February. But Iran and the six powers involved failed to meet an initial self-imposed July 20 deadline to negotiate a deal.

The six, comprising Britain, China, France, Germany, Russia and the United States and known as the P5+1, have agreed to extend negotiations until Nov. 24.