Iranian Supreme Leader Ayatollah Ali Khamenei has said his country requires nearly 19 times more centrifuges than what the world powers are offering in the proposed nuclear agreement.

Iran's ultimate authority said on his website: "Their aim is that we accept a capacity of 10,000 separative work units, which are equivalent to 10,000 centrifuges of the older type that we already have. Our officials say we need 190,000 centrifuges. Perhaps not today, but in two to five years that is the country´s absolute need."

The sanctions-hit country is presently estimated to possess about 19,000 centrifuges, out of which more than half are operational.

As part of the ongoing nuclear talks, which aim to strike a permanent accord between Iran and world powers, the Iranian delegates earlier sought about 50,000 centrifuges while the West insists on limiting the number to a few thousands or a maximum of 10,000.

The interim deal between Iran and P5+1 powers - the UK, US, China, Russia, France and Germany - expires on 20 July and negotiations are on for a permanent agreement. The sixth round of talks began on 2 July in Vienna.

Khamenei's remarks come at a time when the Western powers have said Iran has agreed to reduce the number of centrifuges, but not up to the level desired by the world powers.

"The P5+1 started bargaining with 500 SWUs [separative work units], then 1,000 SWUs enrichment capacity. Now they want to convince us to [accept] 10,000 SWUs," said the Iranian leader.