Geneva, Dec 17 (IANS): World powers and Iran resumed talks here in Geneva Wednesday over Tehran's nuclear programme in the first round after the failure to meet a Nov 24 deadline for a comprehensive nuclear deal.

The plenary meetings of the P5 1 group -- namely China, France, Russia, Britain, the US, plus Germany -- and Iran began Wednesday morning, and were expected to last all day long, Xinhua reported citing a diplomatic source, without giving further details.

Bilateral and trilateral engagements have been held in the Swiss city to pave ways for progress during the past two days before Wednesday's negotiations.

Iranian diplomats noted that all nuclear issues would be discussed in this round of talks.

Wang Qun, director-general of the Chinese foreign ministry's department of arms control, who heads the Chinese delegation to the talks, said Wednesday that "we have to face the difficulties before us, but on the other hand we will do our very best".

Russian Deputy Foreign Minister Sergey Ryabkov reportedly said Wednesday that the Arak nuclear reactor and sanctions imposed against Tehran are the two major sticking points for the Iran nuclear talks.

Iran has been a target of UN sanctions due to its alleged attempts to build nuclear weapons. The West accuses Iran of developing nuclear weapons under the cover of civilian nuclear programme, which Iran has denied, insisting that its nuclear programme was for peaceful purposes only.