The Iranian president, Mahmoud Ahmadinejad, said Wednesday that his nation would produce a higher grade of nuclear fuel on its own, escalating its war of words with the international community over its disputed nuclear program.

His declaration continued a daily drumbeat of defiant proclamations from the Iranian leadership, which has vowed to expand its nuclear plants and hone its capability to enrich uranium despite strong warnings from the United Nations and Western powers that its program violates its commitments under the Nuclear Nonproliferation Treaty.

“I declare here that, with the grace of God, the Iranian nation will produce 20 percent fuel and anything it needs itself,” Mr. Ahmadinejad told a cheering crowd in the central city of Isfahan, according to the Reuters news agency.

Iran claims it needs a relatively high grade of nuclear fuel for civilian uses. But many in the West suspect its program is aimed ultimately at producing atom bombs.