BOULDER, Colo. (AP) -- The U.S. Energy Department has extensive technical expertise that will help verify whether Iran is complying with its commitment to limit its nuclear program under an international agreement, the U.S. energy secretary said Monday in Colorado.

The deal negotiated by the U.S. and other world powers relied heavily on the Energy Department's knowledge, Secretary Ernest Moniz said in a speech at the University of Colorado Law School.

"Our nuclear expertise is unmatched in scope and scale," he said. "It inspires confidence in the soundness of the nuclear dimensions of the Iran agreement."

The deal calls for limiting Iran's nuclear program in exchange for lifting economic sanctions.

Congressional Republicans oppose the agreement, but at least 31 Democratic senators have announced support for it. If the Senate passes a resolution disapproving of the deal, backers would need 34 votes to uphold a presidential veto of the measure.

Moniz defended the agreement and said the U.S. has the science-based capability to detect cheating.

The Energy Department has developed computer simulations and laboratory technology to ensure the reliability of the U.S. nuclear arsenal without test explosions, he noted, and those abilities helped structure the Iran deal and will help monitor it.

The Energy Department's National Nuclear Security Administration is responsible for ensuring the reliability and safety of the U.S. nuclear arsenal and for promoting nuclear nonproliferation.

"Science also underpins everything the United States does to counter nuclear proliferation and nuclear terrorism," Moniz said. He cited previous U.S. successes in helping Russia convert 500 tons of high enriched uranium into fuel for U.S. nuclear reactors.

In a separate meeting with climate scientists at the university, Moniz said state and regional efforts to assess and counter climate change hold promise.

"We are really emphasizing a lot more focus on regions," he said, saying states have a critical role in addressing climate change.

This article was written by Dan Elloitt for AP on Aug. 31, 2015