Manchester City defender Jason Denayer "regrets" becoming involved in a brawl outside a Brussels nightclub in which he "reacted instinctively" by kicking out at a man punching his friend.
An eight-second video of the incident - which took place on Sunday - shows the 21-year-old striking a man who is punching another man on the floor.
A longer version shows how Denayer, at first reluctant to intervene, strikes out when his friend is pinned down.
"I reacted instinctively," he said.
"Of course I regret to have been caught up in a conflict that was not mine to begin with, but I saw my friend was in real danger and I had to interfere and protect him.