Rouhani, who instigated the negotiations, made the comments while justifying his nuclear policy and Iran's progressive disengagement from the accord. He also stated his willingness to continue dialogue on the agreement.

"Today, we are under no restrictions in the area of nuclear energy," he said during a speech in Tehran.

"Our daily enrichment (of uranium) is higher than it was before... the agreement," he added, in remarks apparently directed at Iranian ultraconservatives who denounce his nuclear policy as a total failure.

Rouhani did not specify whether Iran was now producing a greater quantity of enriched uranium, or whether it was enriching ore with uranium 235 isotopes at a higher level than before the deal.

The 2015 agreement was struck in Vienna between Iran and France, Britain, Germany, the United States, China and Russia.

But it has threatened to collapse since President Donald Trump unilaterally withdrew the United States in 2018, before reimposing a series of intensifying economic sanctions on Iran.

In response, Tehran has progressively reduced a number of its key commitments to an agreement that drastically limited its nuclear activities.

Iran is now producing uranium enriched beyond the 3.67 percent set by the agreement, and no longer adheres to the limit of 300 kilogrammes (660 pounds) imposed on its enriched uranium stocks.

The Islamic republic announced on January 5 that it was no longer bound by limits on the number of centrifuges it could run to enrich uranium, saying this was its last step back from the commitments it made in Vienna.

Before then, Iran announced it was enriching uranium to a level of five percent, far from the 90 percent needed to produce an atomic bomb. Before the nuclear deal, Iran was enriching uranium to 20 percent.

A source close to the International Atomic Energy Agency told AFP on January 10 that there had been "no notable change in Iran's nuclear activity" since January 5.