CONCORD, N.C. (AP) — Republican presidential candidate Newt Gingrich all but conceded Wednesday that his White House campaign is over.

He said he expects Mitt Romney will be the nominee and called on the party to unite behind the former Massachusetts governor.

“You have to at some point be honest about what’s happening in the real world as opposed to what you would like to have happened,” Gingrich told supporters at a suburban Charlotte, N.C. restaurant the morning after Romney swept primary contests in five states.

“Gov. Romney had a very good day yesterday. You have to give him some credit. He’s worked for six years. He put together a big machine ... I think I would obviously be a better candidate.”

But Gingrich said GOP voters didn’t agree, and that he would begin working to unite the party.

“I also think that it’s very, very important that we be unified,” he said. “No conservative anyplace in America should have any doubt about the importance of defeating Barack Obama.”

Gingrich did not formally withdraw from the race but said he is now campaigning as a “citizen.” He did not explain what he meant.