Paul McGrath has hit out at the Minneapolis police after the death of George Floyd.
A shocking video posted online shows a white police officer kneeling on the neck of the unarmed and handcuffed black man, who later died.
The policeman shown kneeling on Mr Floyd's neck and three fellow officers involved were dismissed from the police department on Tuesday as the FBI opened an investigation.
A video, which emerged on Tuesday, shows Mr Floyd gasping for air and groaning, "I can't breathe," as an officer pins him down with a knee to his throat.
Bystanders beseech the officer to let him up before he appears to lose consciousness, with the video causing outrage in America and around the world.
Hitting out at the incident, Republic of Ireland footballing legend McGrath said on Twitter: "Wow . America the great , just saw a Black young man have his Life ended. White police officer Kneeling on his Neck , for five to six minutes. Oh , by the way the man was handcuffed. Minneapolis must be proud. Bunch of Cowards . R.I.P. GEORGE, FLOYD."
Protesters clashed with riot police firing tear gas for a second night in Minneapolis on Wednesday in an outpouring of rage over the death of Mr Floyd.
The second day of demonstrations, accompanied by looting and vandalism, began hours after Mayor Jacob Frey urged prosecutors to file criminal charges against the white policeman shown pinning Floyd to the street.
Floyd, who was unarmed and reportedly suspected of trying to pass counterfeit bills at a corner eatery, was taken by ambulance from the scene of his arrest and pronounced dead the same night at a hospital.
Hundreds of protesters, many with faces covered, thronged streets around the Third Precinct police station late on Wednesday, about half a mile from where Floyd had been arrested, chanting, "No justice, no peace" and "I can't breathe."
The crowd grew to thousands as night fell and the protest turned into a standoff outside the station, where police in riot gear formed barricade lines while protesters taunted them from behind makeshift barricades of their own.
Police, some taking positions on rooftops, used tear gas, plastic bullets and concussion grenades to keep the crowds at bay. Protesters pelted police with rocks and other projectiles.
Some threw tear gas canisters back at the officers. Television news images from a helicopter over the area showed dozens of people looting a Target store, running out with clothing and shopping carts full of merchandise.
Fires erupted after dark at several businesses, including an auto parts store. Eyewitnesses said the blazes appeared to be the work of arsonists. Media said a smaller, peaceful protest was held outside the home of one of the police officers.
