TEHRAN, Iran (AP) - Iran is pushing ahead with its nuclear program despite the threat of new U.N. sanctions.
The country has increased the number of operating centrifuges at its uranium enrichment plant to 4,000.
The number is up from the 3,000 centrifuges that Iran announced it was operating in November. Still, it's well below the 6,000 it had said last year that it would be operating by this summer. That suggests the program may be behind schedule.
A government official says Iran is preparing to install even more centrifuges, but didn't offer a timeframe.
The U.N. has already imposed three rounds of sanctions against Iran for refusing to freeze its enrichment program. The program can be used to produce either fuel for a nuclear reactor or material for a nuclear warhead.