WASHINGTON, Nov 26 (Reuters) - The United States believes new information, including evidence of new facilities, will turn up in the next few months showing Iran is in violation of its nuclear commitments, a U.S. official said on Wednesday.

He spoke with Reuters after the United Nations watchdog agency condemned Iran over an 18-year cover-up of sensitive atomic research and said any future breach of non-proliferation obligations would not be tolerated.

"I think there is going to be material and disclosures over the next few months that will show Iran is still in violation," the official said.

"I don't know what will be the first point to break. We're most concerned about Iran's enrichment program and whether Iran owned up to all details of that program," he said.

He noted that "every few months we seem to discover new Iranian nuclear facilities. ... I think more facilities will come to light."

The information is expected to come from Iranian opposition groups, who have often revealed details of Iran's covert program, or "from a friendly state that has sources and information," he said.

The official, who spoke on condition of anonymity but monitors the Iranian program closely, refused to provide any more details but said: "There are a lot of intelligence agencies in the world that could provide information on Iran."

During a board meeting in Vienna, the U.N. watchdog, the International Atomic Energy Agency, stopped short of reporting Iran to the Security Council, which could have imposed sanctions. But U.S. officials say Tehran has more secrets and eventually will face the U.N. body.

Iran denies pursuing a nuclear weapons program.