Iran's president says his country now has 6,000 centrifuges capable of enriching uranium.

That's double the number of machines Iran previously said it was operating.

Mahmoud Ahmadinejad's announcement comes a little more than a week after the U.S. reversed its stance towards negotiations with the Islamic state.

The U.S. and other world powers hoped to reach a deal that would stop Iran from expanding its nuclear program.

Secretary of State Condoleeza Rice later accused Iran of not being serious at those talks.

She also warned that Iran would face yet another round of UN sanctions if it refused to back off it's nuclear ambitions.