Top diplomats are calling the summit "constructive." The U.S. and other nations are hoping to convince Iran to end the enrichment of uranium that could be used to make nuclear bombs.
In the meantime, a top Iranian cleric in Tehran insisted Friday the nuclear program is designed only for peaceful uses. Vice president of the European Commission Catherine Ashton says the country has a right to a peaceful nuclear program, but the Nuclear Proliferation Treaty must be the "key basis" for future talks.
The EU foreign policy chief says the two sides will meet again in Baghdad on May 23.
The Associated Press contributed to this report.