With virtually no public discussion or debate, the Army commandos are helping locate and destroy caches of ballistic missiles and launch sites that Houthi rebels in Yemen are using to attack Riyadh and other Saudi cities.

Details of the Green Beret operation, which has not been previously disclosed, were provided to The New York Times by United States officials and European diplomats.

They appear to contradict Pentagon statements that American military assistance to the Saudi-led campaign in Yemen is limited to aircraft refueling, logistics and general intelligence sharing.

There is no indication that the American commandos have crossed into Yemen as part of the secretive mission.