MANCHESTER, N.H. — Republican presidential hopeful Newt Gingrich canceled an appearance at his New Hampshire campaign headquarters after protesters swarmed the entrance.

About 40 protesters showed up Monday evening carrying placards reading "Ron Paul" and "Occupy." One played speeches by presidential candidate Ron Paul from a loudspeaker.

The former House speaker's private security detail decided to cancel the event because of security concerns regarding the entrance and exit to the building, Gingrich spokesman R.C. Hammond said.

About 75 supporters and volunteers had crammed into the Manchester office to see Gingrich the night before the New Hampshire primary. The Gingrich campaign volunteered to transport them to his next event Monday night, set at a bar in Concord, N.H., to watch a college football game.