A new round of talks on Iran's controversial nuclear programme have opened in the Russian capital, Moscow, - BBC reported.

The two-day meeting between Iran and six world powers follows inconclusive sessions in Istanbul and Baghdad over the last two months.

Earlier this month, the UN's nuclear watchdog admitted that its talks with Tehran had ended with "no progress".

The West suspects that Iran is seeking to build a nuclear weapon - a claim denied by Tehran.

The talks between negotiators from Tehran and six world powers - Britain, the US, China, Russia, France and Germany - are due to start at 0700 GMT.

The powers are expected to repeat three specific demands made last month, the BBC's James Reynolds in Moscow reports.

Our correspondent says that they want Iran to stop enrichment of uranium to 20%, to export its stockpile of 20%-enriched uranium and to to close a heavily-fortified underground enrichment facility near the city of Qom.

In return, the world powers say that they are prepared to start by offering help with nuclear safety measures.

But for Iran that is not enough, our correspondent says.

Tehran wants the West to lift sanctions, including an EU oil embargo and US measures against Iran's Central Bank.

It also says that Iran's "non-negotiable" right to enrich uranium must be recognised.

The UN's nuclear watchgod, the International Atomic Energy Agency (IAEA) had been trying to get access to sites inside Iran, including one at Parchin suspected of being used for experiments related to nuclear weapons.

However, the IAEA's chief inspector Herman Nackaerts said earlier this month that the lack of progress at talks in Vienna had been "disappointing".

Last November, an IAEA report claimed Iran had "carried out activities relevant to the development of a nuclear device".

Iran denies its nuclear programme has any military aspect.