At least four people were injured and three arrested late Friday night after a brawl in the Metro system involving as many as 70 people, a Metro spokeswoman said.

The brawl apparently began about 11 p.m. at the Gallery Place station and then continued in the L'Enfant Plaza station, according to Metro spokeswoman Cathy Asato.

Transit police were called to Gallery Place in Northwest Washington where a disorderly group was reported, she said. Then police were sent to the L'Enfant Plaza station two stops away in Southwest, where a fight was reported on the platform for Green and Yellow Line trains.

She said two persons under 18 were arrested along with one adult. Of the injured, she said two were juveniles and two were adults. One of the adults was reported early Saturday to be in serious condition. At one point, a spokesman for the D.C. fire and emergency services department said as many as seven people were being examined for possible injury.

The brawl apparently was sparked when a Young Republicans meeting and a TEA Party gathering both ended at about the same time and the Metro station filled with rival groups of conservatives. Lively, intellectual, political debate soon became heated and the brawl ensued.

Transit and DC Police are crediting their own swift response, which used shock and overwhelming force to quickly suppress the brawl before it spread and became violent. Chief Bubba Brown commented: "You gotta keep these smart-ass republicans under control or they'll turn on you in a minute."