TEHRAN, Iran - The United States is incapable of inflicting "serious damage" on Iran, President Mahmoud Ahmadinejad said yesterday. As he spoke, a second U.S. aircraft-carrier group steamed toward the Persian Gulf, a warning from Washington for Iran to back down in its attempts to dominate the region.

In an interview with Iranian state television, Ahmadinejad said the United States had not stepped up its campaign against Iran, despite the standoff with the West over Iran's defiance of U.N. demands to halt uranium enrichment. The U.N. Security Council imposed limited sanctions on Iran last month.

"U.S. rhetoric against Iran has not increased," he said. "In 2003, they openly threatened to attack Iran. Now they have indirectly made such threats."

He spoke with confidence over Iran's ability to withstand a strike. "The United States is unable to inflict serious damage on Iran," he said.

Iran says its atomic program is aimed solely at generating energy. The United States and some of its allies suspect it is geared toward making nuclear weapons.

Ahmadinejad, during a meeting yesterday with Syrian Foreign Minister Walid Moallem, accused the United States of stirring up conflict between rival Muslim sects to maintain influence in the Middle East.

"The U.S. intends to cause insecurity and dispute and weaken independent governments in the region to continue with its dominance over the Middle East and achieve its arrogant goals," Ahmadinejad said, according to the state-run Islamic Republic News Agency.

Nicholas Burns, U.S. undersecretary of state for political affairs, ruled out direct negotiations with Tehran and said a rapprochement was "not possible" until Iran halted uranium enrichment.

"The Middle East isn't a region to be dominated by Iran," Burns told the Gulf Research Center, a think tank based in the United Arab Emirates. "The gulf isn't a body of water to be controlled by Iran. That's why we've seen the United States station two carrier battle groups in the region."

The aircraft carrier John C. Stennis and accompanying warships have been sent to the gulf as part of a buildup of forces that Defense Secretary Robert Gates has said sought to impress on Iran that the four-year war in Iraq had not made the United States vulnerable.

The Stennis, expected to arrive in late February, will join a carrier group already in the region, led by the Dwight D. Eisenhower.