White House National Security Adviser Stephen Hadley said on Sunday that the United Nations is the preferred forum to solve Iran's nuclear issue.

Hadley made the statement during an interview with the CNN. He again dismissed calls for direct talks with Iran to resolve the stand-off over its nuclear program.

He said Iran has a lot of opportunities to make the right decision, which is a response to the will of the international community to halt its uranium enrichment program and abandon production of nuclear weapons.

The United States is looking at kinds of sanctions or kinds of benefits that might be applied according to Iran's choice, Hadley added.

Iranian President Mahmoud Ahmadinejad said on Saturday that Iran was willing to talk with any country except Israel.

Besides, UN Secretary-General Kofi Annan urged the U.S. on Friday to start direct talks with Tehran, considering it the best way to solve the problem.