Iran and world powers agreed on Saturday, April 14 to hold a new round of talks in Baghdad on May 23, European Union foreign policy chief Catherine Ashton said after the first meeting in more than a year on Tehran's disputed nuclear program, Reuters reported.

"We want now to move to a sustained process of dialogue ... We will be guided by (the) principle of step by step approach," Ashton told a news conference, calling the first meeting useful and constructive. "We will meet on May 23 in Baghdad."

Iran insists its nuclear program is peaceful, and Ashton said that Tehran has a right to such a peaceful program. At the same time, she added, the Nuclear Nonproliferation Treaty must be the "key basis" for future talks.