Secretary of Defense Ash Carter said Thursday that Iran’s videotaping of American sailors surrendering aboard their boats in the Persian Gulf earlier this month made him deeply angry.

In the video, the 10 Americans were on their knees with their hands on the heads, as Iranian troops took them and their boats into custody. They were released the following morning.

The boats had crossed into Iranian territorial waters for reasons the US Navy has not yet fully explained.

Carter said that if the circumstances were reversed, US forces would not have videotaped captured Iranian sailors.

He said he has no reason to think the US sailors acted inappropriately. One of them admitted on camera that the boats had strayed into Iranian waters, and he apologized for that.

US Defense Secretary Ash Carter addresses American troops at the Incirlik Air Base near Adana, Turkey, Tuesday, Dec. 15, 2015. (AP Photo)

US Defense Secretary Ash Carter addresses American troops at the Incirlik Air Base near Adana, Turkey, on December 15, 2015. (AP)