Iran has agreed with world powers to begin implementing an agreement in late January obliging Teheran to suspend its most sensitive nuclear work, an Iranian official was quoted as saying on Tuesday.

There was no immediate confirmation of the agreement from the six powers - the United States, Russia, China, France, the United Kingdom and Germany - or from the European Union, which oversees contacts with Iran on behalf of the six.

The reported agreement follows nearly 23 hours of talks between nuclear experts from Iran and the six powers held in Geneva on Monday and Tuesday.

The seven countries have met several times since reaching the breakthrough accord on Nov 24 to iron out practical details and decide when the deal would be implemented.

An Iranian nuclear negotiator, Hamid Baeidinejad, said a date was agreed upon on Tuesday.

"The implementation of the Geneva accord will start in the third 10-day period of January," Baeidinejad said on Iranian Press TV.

"The two sides managed to reach an understanding on the implementation of the agreement, and now their views and interpretations are the same," he said.

The EU, the UK and the US indicated, however, that work remains to be done on how to implement the November accord.

Michael Mann, a spokesman for EU foreign policy chief Catherine Ashton, said the experts would report back to their capitals and contacts would continue that will "finalize a common understanding of implementation".

He declined to comment on Iran's assertion that there had been an agreement on the timetable for implementing the accord.

In Washington, US State Department spokeswoman Marie Harf said progress was made in the talks and the sides "expect to finalize the implementation plan soon".

A senior US administration official said that agreement was near.

In London, a Foreign Office spokeswoman said good progress had been made in the latest talks in Geneva, but some issues remained to be resolved.

"Our aim is to bring the agreement into force as soon as possible," she said.

Western diplomats have said in the past that Jan 20 was a possible implementation date, because that is when EU foreign ministers next meet in Brussels and could agree on the lifting of EU sanctions.

Western countries led by the United States fear that Iran's nuclear work has military goals and have imposed years of sanctions on Iran in an effort to force Teheran to curb its nuclear program.

Iran denies seeking to build an atomic bomb and says its nuclear work is aimed at power generation and medical research.

Under the Nov 24 agreement, Iran will suspend its most sensitive uranium enrichment efforts and, in return, Western governments will ease some economic sanctions.

The sequence of these moves appeared to be a sticking point in the expert talks, with divisions over how much advance notice Iran will give Western governments that it is meeting its end of the deal before they lift the agreed sanctions.

Reuters