"We have had constructive and valuable discussions and we are encouraged by the progress made, reflecting shared international concern about Iran's nuclear program and the important issues at stake," the spokeswoman for the Foreign Office told Xinhua.

"We focused on both elements of the approach. Political directors will now report to capitals, including on a proposal that ministers should meet in the near future to take final decisions," said she, adding "preparatory work will continue over the coming days."

"This is a complex and sensitive diplomatic negotiation." said she.

But she gave no details of what had been discussed among senior officials from the United States, Russia, China, Britain, France, as well as Germany.

The meeting was postponed last Friday for "more detailed preparations on the EU-3 proposals" to Iran.

Last week, the EU was prepared to offer a cooperation deal, in order to find a diplomatic solution to Iran's nuclear issue. The deal is likely to include an offer of a light-water reactor and an assured supply of nuclear fuel for civilian atomic plants so Iran would not enrich uranium itself.

But Iranian President Mahmoud Ahmadinejad said Iran would reject a deal with the EU which plans to offer incentives in exchange for Iran's halting uranium enrichment.