PITTSBURGH, September 26 (RIA Novosti) - U.S. President Barack Obama said on Saturday that he does not rule out the use of force against Iran but prefers diplomatic methods to resolve the nuclear problem.

"We do not rule out any options when it comes to U.S. security interests," he said, adding that everything depends on Iran.

Otherwise, he said, Tehran will face "sanctions that bite," but he did not specify the nature of sanctions.

The UN nuclear watchdog confirmed media reports on Friday that Tehran had informed it on Monday of the construction of a second uranium enrichment plant. The belated disclosure is likely to fuel Western powers' suspicions that Iran is seeking nuclear weapons.

The U.S. president and leaders from Britain and France condemned Iran on Friday for the secret construction of its second uranium facility.