Stalled negotiations between world powers and Iran on Tehran's controversial nuclear programme will likely resume on December 5 in Geneva, the European Union's top diplomat said Monday.

EU foreign policy chief Catherine Ashton told reporters she had received "informal confirmations" from Iran about the date and location for the talks, "but I want a formal confirmation."

Iran and six world powers -- the United States, Russia, China, France, Britain and Germany -- have agreed to return to the negotiating table for the first time since October 2009.

The six powers rejected an Iranian proposal to hold the talks in Turkey. Instead, they suggested meeting in Switzerland or Austria, but the Islamic republic has yet to respond.

The two sides diverge on what issues should be on the table. The world powers want the talks to focus on Iran's uranium enrichment programme but Tehran wants a wider discussion that includes regional security issues.

"For me the core of the agenda is very clear: we need to talk about nuclear weapons capability and to have a full and frank discussion about that," Ashton said.

"But in the course of our discussions, of course, opportunities to raise other issues should not be lost, that is why I want to spend time so that we can do that," she said, noting that she proposed two days of talks.

"But I know what I'm going to discuss," said Ashton, referring to the nuclear dispute.

The United States, Europe and Israel fear that Iran wants to use nuclear technology to build a bomb, but Tehran insists that its programme is a peaceful drive to produce civilian energy.