Uruguay players clashed with Colombia fans following the Copa America semi-final on Wednesday before security personnel stepped in to restore order.
After Colombia sealed a 1-0 victory in Charlotte, North Carolina, videos on social media showed what appeared to be Uruguay players climbing into the stands and exchanging blows with opposition fans.
South American football's governing body CONMEBOL said it is investigating the incident.
Uruguay captain Jose Maria Gimenez said the players were trying to defend their families.
"Let me say something before they cut you off because they won't let us speak into the microphone, they don't want me to say anything about what's going on but this is a disaster," Gimenez said on the official broadcast.
"Please be careful, our families are in the stands, there are little newborn babies. It was a disaster; there was no police and we had to defend our families.
"This is the fault of two or three people who had a few too many drinks and don't know how to drink."
Jefferson Lerma's first-half header gave Colombia a place in Sunday's final while Uruguay will play Canada in the third-place playoff.