Iran has acknowledged for the first time that it has bought nuclear equipment on the black market.
Tehran insists its nuclear programme is for energy
A foreign ministry spokesman said certain items were bought from international dealers, including some from the Indian subcontinent.
Hamid Reza Asefi did not say what had been bought or from what countries.
The admission follows recent revelations from Pakistan's top nuclear scientist that he sold nuclear secrets to Iran, Libya and North Korea.
Malaysian police said on Friday that agents for the Pakistani scientist, Abdul Qadeer Khan, had sold Iran $3m of centrifuge equipment in the mid-1990s.
Police said the disclosure came from Dr Khan's alleged financier, Malaysia-based businessman Buhary Syed Abu Tahir.
Mr Asefi said on Sunday: "We purchased some parts from some dealers but we don't know what was the source or which country they
"It happened that some of the dealers were from some subcontinent countries."
He repeated Iran's position that its nuclear programme was for peaceful purposes - as a means of providing energy.
The US accuses Iran of pursuing nuclear weapons.
Inspection report due
Iran admitted last year that it had been covering up its nuclear activities for years and has now promised full co-operation with the United Nation's nuclear watchdog, the International Atomic Energy Agency (IAEA).
The IAEA is due to release an interim report later this week on nuclear inspections in Iran.
Western diplomats in Vienna said inspectors had found undeclared components of an advanced uranium-enrichment centrifuge at an air force base.
Tehran has strongly denied the report.