Iran continues to acquire uranium and is close to finishing a factory where it can build more centrifuges to enrich it, the country’s nuclear chief said Wednesday, adding also that uranium stockpiles have nearly doubled in the last few years.

The comments by Ali Akbar Salehi, head of Iran’s Atomic Energy Organization, came as Tehran is in talks with major powers on preserving a 2015 deal meant to keep the country from developing nuclear weapons in the wake of President Donald Trump’s decision to pull the United States out of the accord.

Salehi said on state television that Iran has imported some 400 tons of so-called yellowcake uranium since the 2015 landmark nuclear deal, bringing its stockpile to between 900 and 950 tons — up from 500 tons.

Since the 2015 deal, Iran has purchased yellowcake from Kazakhstan and Russia, as well as mined its own domestically. The accord allows for that, but limits Iran’s enrichment of uranium to 3.67 percent, enough to use in a nuclear power plant but far lower than the 90 percent needed for an atomic weapon.

The U.S. pulled out of the deal in May, and since then the remaining countries — Russia, China, Germany, France and Britain as well as the European Union — have been negotiating with Tehran to try and save the agreement with economic incentives and guarantees. Following the U.S. withdrawal, Iran vowed to boost enrichment capacity to put pressure on the remaining signatories to live up to the agreement.

In addition to announcing the continued purchases from Russia and elsewhere, Salehi said Iran is also working on exploration to find additional resources inside the country to meet more uranium needs domestically.

Salehi said Iran has also almost completed a factory aimed at building new generation of centrifuge machines showed in June for the first time.

Also in June, Iran said it has restarted production at a “major” uranium facility involved in its nuclear program in central city of Isfahan, which produces material needed to make enriched uranium.

Iran’s only nuclear power plant in southern Iranian Bushehr went online in 2011 with help of Russia requires some 27 tons fuel per year.

(AP)