Several witnesses accused the police of provoking panic by attempting to disperse crowds outside the ground.
Several witnesses accused the police of provoking panic by attempting to disperse crowds outside the ground in the northern town of Uige at the game earlier this month.
Hundreds of fans were reported to have turned up without tickets for the clash between Santa Rita de Cassia and Recreativo de Libolo in Angola's domestic league season.
"The FAF concludes that flaws in the security plan outside the stadium of Uige caused the incident," the Angola Football Federation (FAF) said after an investigation ordered by the sports ministry.
The official death toll was 17 dead and 58 injured, though medical officials interviewed by AFP reported at least 25 dead.
"It was a serious error to allow so many people to get so close to the stadium. Many people didn't have a ticket and that created confusion," President Eduardo dos Santos said the day after the stampede.
The Recreativo club called it "a tragedy without precedent in the history of Angolan football".