The boy had been arrested on suspicion of wounding with intent after a stabbing in Gipton on Wednesday.
He was taken to hospital in a car and treated for two minor wounds to his abdomen.
Also in the news: All-night rave on Kirkstall Valley Nature Reserve sparks concerns for wildlifeHis wounds were not considered life-threatening, police said.
Officers stepped up patrols in the area following the fight, to reassure residents.
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