The production of 5%-enriched uranium was continuing using first-generation centrifuges and a second generation of machines unveiled last year were in use, he said.
He then announced that experts at the Atomic Energy Organisation of Iran (AEOI) had managed to design a third generation.
"The machines have successfully passed mechanical tests and it is expected that they will have a gas-separation power of nearly 10, which is six times more than the first generation of centrifuges," he said.
At the end of Mr Salehi's speech, President Mahmoud Ahmadinejad stepped onto the stage and pulled back a curtain to reveal one of the new centrifuges.
"Today, Iranian scientists have command over all nuclear energy fields. This does not mean that we are at the peak. But in terms of technical know-how and knowledge, there is no hurdle in their way," he said.
The centrifuges spin uranium hexafluoride (UF6) gas at high speeds to separate the fissile U-235 atoms from the denser U-238 atoms.
The new models are more advanced than the P1 centrifuge - adapted from a 1970s design, reportedly acquired by Iran on the black market in the 1980s, and prone to breakdowns - in use at the Natanz enrichment facility, in the central province of Isfahan.
BBC Tehran correspondent Jon Leyne, who is in London, says nuclear experts point out that the key question is how many of the third-generation centrifuges Iran can produce.
The IAEA says Iran has 3,772 operating centrifuges, mostly at Natanz
There have already been technical problems with the existing models, so whether it can quickly put the new one into mass production and operation remains to be seen, our correspondent says.
Most of Iran's uranium is enriched to a level of 3.5%, but it requires 20% enriched uranium for its Tehran research reactor, which produces medical isotopes. A bomb would require uranium enriched to at least 90%.
The International Atomic Energy Agency (IAEA) said in a report in February that Iran had achieved enrichment levels of up to 19.8%, which added to its concerns about the "possible military dimensions" of its nuclear programme.
Experts say the technical leap required to get to 90% enrichment from 20% is relatively straightforward, because it becomes easier at higher levels. Going from the natural state of 0.7% enrichment to 20% takes 90% of the total energy required, they add.
The IAEA report said 8,610 centrifuges had been installed in known enrichment facilities in Iran, of which 3,772 were operating.
Iran says it will eventually install more than 50,000 centrifuges at Natanz, and build 10 more enrichment facilities at protected sites.
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