The European Union on Wednesday announced new talks between senior EU and Iranian diplomats on Tehran's disputed nuclear drive following expert-level closed door talks in Istanbul this week.

As agreed at talks between the major powers and Iran in June in Moscow, "the technical meeting in Istanbul will be followed by a meeting between Helga Schmid and Dr. Ali Bagheri," said a statement from the office of EU foreign policy chief Catherine Ashton.

The two diplomats have been in regular contact as global powers seek to reach an understanding with Iran over its disputed nuclear programme, Schmid working with the EU and Bagheri assisting chief Iranian negotiator Saeed Jalili.

No date was given for their meeting however.

The Istanbul talks Tuesday between nuclear physics experts from Iran and the major powers known as the P5+1 -- the five permanent members of the UN Security Council and Germany -- took place without the participation of diplomats.

The statement from Ashton's office said the "technical discussions took place in Istanbul on 3rd July. These were led by nuclear expert Stephan Klement on behalf of Catherine Ashton, EU High Representative, with experts from the P5+1 meeting with the Iranian team."

The experts provided further detail of a proposal given to Iran in Baghdad while Iran shared further detail of their proposal, the statement said.

"The experts explored positions on a number of technical subjects. The meeting lasted for a full day ending at 1am," it added.

The technical level resumption of talks over Iran's controversial nuclear aims was set after the last summit between the P5+1 and Iran in June in Moscow.

The downgraded expert round of talks came as Iran hardened the tone of its criticism against the Western countries for dragging out the negotiations.

Iran is insisting it has a "right" to uranium enrichment under the nuclear Non-Proliferation Treaty, which should be recognised by the P5+1. It also wants Western sanctions punishing its economy to be eased.

The world powers instead are pushing for an immediate end to Iran's enriching uranium to 20 percent purity -- just a technical step short of the 90 percent needed to make nuclear bombs -- and to ship out its existing 20-percent stock and close a fortified underground enrichment facility in Fordo.