By ALI AKBAR DAREINI
"The president announced the start of the phase of installing 6,000 new centrifuges in Natanz," state television reported.
Iranian state television did not say if the installation of the 6,000 new centrifuges included the older P-1 or the advanced IR-2 centrifuges.
Iran says it plans to move toward large-scale uranium enrichment that ultimately will involve 54,000 centrifuges.
On Tuesday, China said it would host a meeting of officials from the five members of Security Council and Germany, as well as the EU, to discuss ways to restart negotiations with Iran on its nuclear program.