OXON HILL, Md. (AP) — Republican Mitt Romney apologized for losing the presidential election as he returned to the national stage on Friday, promising to work in a diminished role alongside conservative activists to help strengthen the GOP.

"Each of us in our own way will have to step up and meet our responsibility," Romney told a crowded ballroom at the Conservative Political Action Conference, a three-day summit for activists in suburban Washington.

"I am sorry that I will not be your president," Romney said, taking the stage for the first time since last fall's election loss. "But I will be your co-worker, and I will work shoulder-to-shoulder alongside you."