The two players engaged in a fight after an incident on the pitch at the end of a team practice in Opalencia and had to be torn apart by Seleccao coach Paulo BentoPortugal defender Miguel Lopes and attacker Ricardo Quaresma came to blows during a training session on Saturday.
The incident happened towards the end of a team practice when the Braga man made a robust challenge on the Besiktas winger, who responded angrily to the tackle and aimed a kick at the right back.
The two players went on to hurl verbal abuse at each other amid a lot of pushing, and had to be torn apart by coach Paulo Bento and defender Ricardo Costa, who confirmed the rumors about the bust up to the media.
"These are things that can happen in training," the Valencia centre-half revealed at a press conference.
"There was rather strong challenge for the ball. We’re virile, we always want to win challenges, and sometimes small incidents happen."
Portugal qualified for the semifinals of Euro 2012 after a 1-0 win over Czech Republic and will meet the winner of the fixture between Spain and France in the next stage of the competition.