Iran boasted of the progress of its nuclear programme on Thursday, just a day after the Obama administration took its latest step to find a diplomatic solution to the dispute.

At an event in the central city of Isfahan, Mahmoud Ahmadi-Nejad, Iran’s president, said Tehran was mastering nuclear technology, while Gholam-Reza Aghazadeh, the head of Iran’s Atomic Energy Organisation, said that 7,000 centrifuges had been installed in an underground facility in Natanz.