(CBS News) Sen. Scott Brown, R-Mass., has issued his "one and only warning" to members of his staff captured on camera making "tomahawk" gestures and chanting Indian war whoops during a campaign rally in apparent mockery of Democratic challenger Elizabeth Warren's claim of Native American roots.
"Senator Brown has spoken to his entire staff - including the individuals involved in this unacceptable behavior - and issued them their one and only warning that this type of conduct will not be tolerated," Brown spokesperson Alleigh Marre said in a statement, according to the New York Times. "As we enter the final stretch of this campaign, emotions are running high, and while Senator Brown can't control everyone, he is encouraging both sides to act with respect.
"He regrets that members of his staff did not live up to the high standards that the people of Massachusetts expect and deserve," she concluded.
Brown's warning came shortly after Principal Chief of the Cherokee Nation Bill John Baker called on the senator to apologize for "the offensive actions of his staff and their uneducated, unenlightened and racist portrayal of native peoples."
"The conduct of these individuals goes far beyond what is appropriate and proper in political discourse," the chief said. "The use of stereotypical 'war whoop chants' and 'tomahawk chops' are offensive and downright racist. It is those types of actions that perpetuate negative stereotypes and continue to minimize and degrade all native peoples."
One video, from outside Brown's campaign stop Saturday at the Eire Pub in Boston, showed several members of Brown's congressional and campaign staffs joining with supporters to use the mocking behavior against shouts from Warren supporters. Another recording, released Wednesday, captured audio of "war whoops" erupting during a campaign event in Chatham, Mass., this summer, after Brown mentioned Warren's self-identified Native American heritage.
Warren's background has been the subject of much debate during the Massachusetts Senate race, with Brown supporters calling on her to provide documented proof of her alleged Native American ancestry. Her campaign
Watch the video from Saturday's campaign stop: