A Senate vote to approve the Keystone XL pipeline Tuesday took an odd turn after Sen. Elizabeth Warren, D-Mass., read the final vote tally as protestors of the pipeline in the Senate Gallery burst into song.

Capitol Police officers dragged out five protestors, including Greg Grey Cloud of the Rosebud Sioux Tribe as he bellowed a tribal song. Grey Cloud, who wore a headdress, continued singing as he was knocked to the floor and pulled to the wall of the hallway.

Protesters were handcuffed with plastic zip-ties while standing shoulder-to-shoulder, facing the wall. Senate Sergeant-at-Arms Drew Willson arrived on the scene as doorkeepers and police officers tried to direct the crowd away from the protesters.

In response to the Nov. 14 House vote to authorize the Keystone XL pipeline, Rosebud Sioux Tribe President Cyril Scott announced that the tribe recognized the action as an act of war.