Tehran said it would introduce new centrifuges to its main enrichment plant near Natanz, which the government says is part of an energy strategy.

Many in the west believe this is a cover for the fast-tracking of its nuclear weapons proghramme. According to diplomatic sources, Iran wants to install more than 3,000 new enrichment machines at its site at Natanz, central Iran, which can process up to five times faster than the current equipment.