Vienna: Iran and six world powers left themselves with a lot to do in a short amount of time after a difficult fifth round of nuclear talks ended on Friday, a month before the deadline for a deal.

The aim is to secure a mammoth deal by July 20 to reduce the programme and ease fears the Islamic republic will get atomic weapons.

Iran denies wanting the bomb and wants punishing UN and Western sanctions lifted.

The parties had “begun the drafting process” and would start the next round of talks on July 2, said a spokesman for EU foreign policy chief Catherine Ashton, who is chief negotiator for the six world powers.

“We have worked extremely hard all week to develop elements we can bring together when we meet for the next round in Vienna,” said the spokesman, Michael Mann.

“We presented each other with a number of ideas on a range of issues, and we have begun the drafting process.”

Officials on both sides said however that although the drafting process had begun, haggling over language concerning the thorniest problems was being put off until later.

“It has been another really tough round,” said a diplomat from one of the “P5+1” six powers late Thursday.

“That doesn’t surprise me or particularly dismay me since from the very beginning we have always known that if a deal was to be done, it was going to be very difficult,” the envoy said.

A second diplomat said earlier this week that Iran was refusing to budge on most issues.