The U.S. and its Western allies are pressing Iran to curb its uranium enrichment programme, which they suspect is aimed at developing a nuclear weapons capability, but Iran refuses and insists its nuclear activity is for purely peaceful purposes.
New Iranian President Hassan Rouhani, a former nuclear negotiator who oversaw a previous deal to suspend Iran's uranium enrichment, has welcomed new talks with world powers over the programme but has insisted on Iran's right to enrich uranium.
Iran has 17,000 older "first-generation" IR-1 centrifuges, of which 10,000 are operating and 7,000 are ready to start operations, the ISNA news agency quoted Fereydoun Abbasi-Davani, outgoing head of the Atomic Energy Organization of Iran (AEOI), as saying.
A May report from the U.N. nuclear watchdog indicated that Iran had by then installed roughly 16,600 IR-1 machines in two separate facilities.
Abbasi-Davani also said there were 1,000 new, more advanced centrifuges ready to start operations, in a reference to IR-2m centrifuges, which once operational would allow Iran to enrich uranium several times faster than the IR-1 machine.
The IAEA in its last report in May said Iran had installed a total of 689 such centrifuges and empty centrifuge casings.
Rouhani on Friday appointed Ali Akbar Salehi, Iran's previous foreign minister, to take over the AEOI. Salehi, who once headed the agency, is seen as a pragmatist, as opposed to the more hardline Abbasi-Davani.
(Additional reporting by Fredrik Dahl in Vienna; editing by Andrew Roche)