TEHRAN (AP) ― Iran will step up its uranium enrichment program by sharply increasing the number of centrifuges used to make nuclear fuel, a senior official said Wednesday, in direct defiance of Western demands.

The statement by Iran’s nuclear chief, Fereidoun Abbasi, is likely to escalate tensions. The West suspects Iran’s nuclear program could be headed toward weapons production and has imposed punishing sanctions to try to persuade Tehran to stop enrichment.

Iran has denied the charges, saying its program is peaceful and geared toward generating electricity and producing radioisotopes to treat cancer patients.

Uranium enriched to a low level is used to produce nuclear fuel for reactors, but high level enrichment would make it suitable for use in atomic warheads.

Abbasi said Iran is making nuclear advances in the face of the severe economic measures imposed by the U.N. and the West.

“Despite sanctions, we will most likely see a substantial increase in the number of centrifuge machines this year. We will continue enrichment with intensity,” Abbasi was quoted by state TV as saying Wednesday. The Iranian calendar year ends on March 20.