VIENNA >> Iran and six world powers have agreed to meet in Vienna starting June 16 for their next round of nuclear talks.

The date and venue were announced Tuesday by the office of EU foreign policy chief Catherine Ashton, who is coordinating the talks.

A statement says the round is to end June 20. It said it was agreed on after “very long and useful” discussions in Istanbul between Ashton and Iranian Foreign Minister Mohammad Javad Zarif.

The United States, Russia, China, Britain, France and Germany are offering to lift all sanctions on Iran if it agrees to substantial cuts in its nuclear program to reduce its technical ability to make atomic arms. Tehran denies wanting such weapons.

The last round ended May 16 with little progress.