Iran and world powers discussed the Islamic Republic’s nuclear energy program on Wednesday, with Tehran saying both sides were inching closer on some issues.

Iran and world powers discussed the Islamic Republic’s nuclear energy program on Wednesday, with Tehran saying both sides were inching closer on some issues.

Iran's lead negotiator Abbas Araqchi said some difference were narrowed, expecting that a new round of talks may take place in mid-May.

"On certain questions we have narrowed our differences," Araqchi told Iranian media late Tuesday after a first day of talks in Vienna that were expected to wrap up later Wednesday.

The negotiations, aiming to settle a decade-old standoff and so avert a dangerous escalation, remained however "difficult and complicated", Mehr news agency quoted Araqchi as saying.

Iranian Foreign Minister Mohammad Javad Zarif and the powers' lead negotiator, EU foreign policy chief Catherine Ashton, were expected to make a statement to the media later Wednesday.

A senior US administration official involved in the talks said last week that the negotiators hoped to make enough progress in this round to begin drafting a deal in May.

In November the two sides reached an interim deal under which Iran froze certain parts of its nuclear activities in return for minor relief from painful Western sanctions.