BOULDER, Colo. — U.S. Energy Secretary Ernest Moniz says his department’s technical expertise will help verify whether Iran is complying with its commitment to limit its nuclear program under an international agreement.

Speaking at the University of Colorado in Boulder on Monday, Moniz said the deal negotiated by the United States and other world powers relied heavily on the Energy Department’s technical expertise in nuclear weapons.

He says the department has developed the computer simulations and laboratory technology to ensure the reliability of the U.S. nuclear arsenal without test explosions.

Moniz says those abilities helped structure the Iran deal and will help monitor it.

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

Congressional Republicans oppose the agreement but the number Democrats supporting it is growing.

U.S. Rep. Joe Kennedy of Massachusetts Monday added his name to the list of Democrats backing the deal, joining a majority of the state’s all-Democratic congressional delegation in supporting the international agreement.

Kennedy said he studied the deal closely and decided to back it not because it’s perfect or without risk, but because it is “rooted in science and anchored by verification.”

Kennedy said he believes the agreement is the international community’s chance to keep nuclear weapons out of the hands of Iran’s leaders.

No member of the Massachusetts delegation has opposed the deal.