Uruguay players clashed with Colombia fans following their Copa America semi-final defeat 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's Darwin Nunez and Ronald Araujo were among the players at the forefront of the melee. 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."
Players and staff from both Colombia and Uruguay were also involved in a confrontation on the field after the final whistle.
"I thought that the incident ended with some argument on the midfield and when I saw that happening I went to the locker room," Uruguay coach Marcelo Bielsa said in a press conference.
"I thought that they were thanking the fans for their support. But then I learned that there were some problems over there unfortunately."
Jefferson Lerma's first-half header gave Colombia a place in Sunday's final while Uruguay will play Canada in the third-place playoff.
—Reuters
