Middle East

Diplomats: UN has warned Iran about enrichment cap

Director General of the International Atomic Energy Agency, IAEA, Yukiya Amano from Japan speaks to the media after returning from Iran at the Vienna International Airport, Austria, Monday, Dec. 19, 2016. Amano was visiting Iran for the second time since a landmark nuclear agreement with world powers went into effect at the start of this year. (AP Photo/Ronald Zak)

Director General of the International Atomic Energy Agency, IAEA, Yukiya Amano from Japan speaks to the media after returning from Iran at the Vienna International Airport, Austria, Monday, Dec. 19, 2016. Amano was visiting Iran for the second time since a landmark nuclear agreement with world powers went into effect at the start of this year. (AP Photo/Ronald Zak)  (The Associated Press)

The U.N. nuclear agency chief says Iran is complying with obligations limiting uranium enrichment. But two diplomats say the agency has warned Tehran that unless it slows the process it could soon bust through its cap on material that could be used to make a bomb.

A nuclear deal between Iran and six world powers stipulates that Iran can possess only low-enriched uranium and only in amounts far less than needed for further enrichment into the fissile core of a nuclear warhead.

The warning comes at sensitive time, with the incoming U.S. administration saying it could push to renegotiate the pact.

The two senior diplomats, whose main focus is Iran's nuclear program, spoke only on condition of anonymity because they are not authorized to discuss the confidential issue.