No agreement after UN Iran talks

Iran has been enriching uranium at its underground facility in Natanz

The United Nations Security Council's five permanent members have held talks in Shanghai to discuss action aimed at curbing Iran's nuclear ambitions.

Envoys from China, the US, Russia, the UK and France met a German negotiator to consider new moves to ensure Iran's nuclear programme remains peaceful.

But a Chinese spokesman said problems still remained and the talks had failed to iron out a new agreement.

Iran is widening its nuclear work in defiance of Security Council demands.

Chinese foreign ministry spokesman He Yafei emerged from the Shanghai talks saying the six nations had agreed to continue diplomatic efforts.

"We can say we agreed on the main content of a plan to restart negotiations, but not all the problems have been resolved," he said.

Last week, President Mahmoud Ahmadinejad said Iran had begun installing 6,000 new centrifuges, used to enrich uranium, at its main nuclear plant in Natanz.

The Security Council, concerned that Iran might process uranium to weapons level, has demanded an end to enrichment.

Tehran insists it wishes only to acquire civilian nuclear energy.

The Shanghai meeting came after talks between Iran's nuclear envoy and the UN's top nuclear monitor were postponed for unknown reasons.

Enrichment 'red line'

Wednesday's talks in China's business hub were meant to follow up on a package of political, security and economic incentives offered to Iran in June alongside further sanctions.

The one-day meeting was intended to send a "positive signal to the world", China's foreign ministry said.

Iranian officials have repeatedly rejected any deal in return for trade and other benefits.

"I don't think it is a bargain Iran will accept," one Iranian analyst told Reuters in Tehran, speaking on condition of anonymity.

"The enrichment programme is the red line at the moment."

Talks due on Monday in Vienna between Iran's Gholamreza Aghazadeh and Mohamed ElBaradei, head of the International Atomic Energy Agency (IAEA), were called off with no reason being given.

The UN Security Council last month approved a third round of sanctions on Iran over its nuclear programme.