U.S. Defense Secretary Pete Hegseth on Friday chided past celebrations of the U.S. military's diversity in a broad address to Pentagon staff in which he also promised a tougher approach to NATO and accountability over the war in Afghanistan.

The defense secretary, speaking to the Pentagon work force, defended his “unconventional approaches” to an audience that included women and people of color.

"I think the single dumbest phrase in military history is, 'Our diversity is our strength. I think our strength is our unity," he said. Hegseth continued: "Our strength is our shared purpose, regardless of our background,