United Nations officials warned, Thursday, that Iran may be working on a nuclear warhead, despite previous reports that Tehran stopped such activities in 2003.

For the first time, the International Atomic Energy Agency expressed concern that Iran could be looking into ways to turn enriched uranium into a weapon.

In response, the White House said Iran is failing to live up to its international obligations and there would be consequences if the country continues to go against its commitments.

Iranian officials deny any interest in making nuclear weapons, but the IAEA report said their resistance to investigations "give rise to concerns about possible military dimensions to Iran's nuclear program."

In 2007, U.S. intellegence concluded Tehran appeared to have suspended nuclear work.