NEW ORLEANS (Reuters) - A comedian impersonating President Barack Obama was cut short and ushered off the stage at a gathering of Republican activists on Saturday after a series of off-color jokes.

The Obama impersonator, Reggie Brown, poked fun at Obama's biracial heritage, a gay congressman and several of the Republican presidential candidates before Republican Leadership Conference organizer Anthony Davis cut him off.

As Obama, whose father was black and mother was white, Brown said he celebrated half of Black History Month.

He also made a joke about Democratic Representative Barney Frank, who is gay, mocked Republican presidential candidate Mitt Romney's Mormon faith and said Republican Tim Pawlenty needed a spinal transplant after his failure to confront Romney on healthcare at a debate earlier this week.

As Brown was launching into a joke about Republican Michele Bachmann, the music came up and Davis came on stage to cut him off.

(Editing by Peter Cooney)