Iran's foreign ministry said on Sunday that the landmark agreement the Islamic republic clinched with world powers on its disputed nuclear programme will take effect from 20 January.

"The implementation of the joint plan of action will start from 20 January," ministry spokeswoman Marzieh Afkham told Mehr news agency.

Under the deal reached in November, Iran agreed to curb parts of its disputed nuclear drive for six months in exchange for receiving modest relief from international sanctions and a promise by Western powers not to impose new measures against its hard-hit economy.