U.S. accuses Iran of defiance on nuclear activity

WASHINGTON (Reuters) - The United States accused Tehran of defying the world community on Wednesday and said it risked further isolation after the international atomic watchdog said Iran had begun making nuclear fuel in its underground uranium enrichment plant.

The International Atomic Energy Agency cited the nuclear activity in a note that became public on Wednesday.

"The IAEA's letter demonstrates the Iranian government's continued defiance of the international community. Iran's leaders continue to lead their proud people down a path of further isolation," said White House National Security Council spokesman Gordon Johndroe.

"While their leaders see this as an advance, it is only a step backward," he added. "Instead of complying with the United Nations Security Council resolutions, Iran's actions may only lead them to more sanctions."

The IAEA note also said Iran had started up more than 1,300 centrifuge machines in an accelerating campaign to lay a basis for "industrial scale" enrichment in the Natanz complex.

The U.N. Security Council has demand that Tehran halt its enrichment program over suspicions that Iran is using its civilian nuclear program as cover to try to develop an atomic bomb.

Tehran insists its nuclear program is intended only for the peaceful purpose of generating electricity.