Iran celebrated its National Day of Nuclear Technology on Saturday with an event held simultaneously in Tehran and nuclear sites in different Iranian cities, during which advanced IR-6 centrifuges started operating, and more than 100 other nuclear industry innovations were unveiled.

During the event, 164 IR-6 semi-industrial centrifuges were injected with gas and became fully operational at Iran's uranium enrichment plant in Natanz, and 30 IR-6S centrifuges entered the first phase of gas injection at the same plant, official news agency IRNA reported.

Broadcast on state TV, Iranian President Hassan Rouhani gave the order from Tehran to introduce uranium hexafluoride gas to the cascades in Natanz and made a short speech to defend the accomplishments of Iran's nuclear program under his administration.

Rouhani said that the United States, European countries and the International Atomic Energy Agency (IAEA) are "in debt" with Iran, since the Treaty on the Non-Proliferation of Nuclear Weapons obliges nuclear states and the IAEA to "help" signatories in their peaceful nuclear activities.

Apart from launching the IR-6 centrifuges in Natanz, other innovations unveiled in the exhibition included the manufacturing and assembly of the first prototype of IR-9S and IR-9-1B centrifuges, currently under mechanical testing, according to official information releases.

"Today, we have reached the IR-9 centrifuge with the capacity of 50 SWU in terms of technology, and they provide us products 50 to 60 times more than those of the old centrifuges," Ali-Akbar Salehi, head of the Atomic Energy Organization of Iran, was quoted as saying at the event by Press TV.

Under the 2015 nuclear agreement, formally known as the Joint Comprehensive Plan of Action (JCPOA), Iran is restricted to only a few first-generation (IR-1) uranium enrichment centrifuges until 2025.

One year after the United States unilaterally abandoned the agreement in May 2018 and reimposed sanctions on Iran, Tehran started reducing its compliance with its JCPOA obligations.

The current U.S. administration has pledged to return to the JCPOA but demands Iran fully comply with its commitments first. Meanwhile, Tehran has demanded that Washington lift all sanctions on the country before it returns to full compliance.

The JCPOA Joint Commission resumed talks in Austria's capital to revive the deal this week, lifting sanctions on Iran and nuclear implementation measures are to top the agenda.