Angry passengers frustrated over a train strike threw bottles and rocks and set fire to entrance doors in Argentina.
Violence broke out after a six hour strike by union workers at the Constitucion train station in Buenos Aires.
Passengers trying to get home for Christmas were left frustrated and began rioting. The police were eventually called and they fired cannons of blue liquid to disperse the crowd.
Several people were arrested and dozens were injured, one seriously.
The Argentine government has said they will file a lawsuit against the union for disruption of public services.
A police official said the passengers were reacting to a blockage of one of the lines by about 20 ex-employees fighting to get their jobs back.