A fight between fans broke out in the stands during an Olympic tennis match involving 2009 U.S. Open champion Juan Martin del Potro of Argentina.
Play was interrupted two games into del Potro's victory over Portugal's Joao Sousa in the sport's main stadium at the Rio de Janeiro Games on Monday, when security guards went into the seats to take away the two spectators involved. 
One was wearing an Argentina national soccer team jersey.
Here are some photos of what happened posted on Twitter:
During the interruption, del Potro plopped himself down on a chair in the corner of the court. 
"The crowd always makes a special atmosphere. It was beautiful _ apart from the incident in the beginning," del Potro said later. "I hope that will not happen again, because people need to enjoy the matches and we need to have peace between Argentina and Brazil."
And he added: "This is not football."