ST LOUIS • Clashes between demonstrators and riot police marred the end of what had been a largely peaceful second day of protest rallies in St Louis, following the acquittal of a white police officer in the fatal shooting of a black man.

Several hundred people gathered near Washington University after dark as the main rallies and marches wound down last Saturday evening. As the night wore on, violence broke out between some of the roughly 100 remaining protesters, some holding bats or hammers, and riot police who ordered them to disperse.

Shop and restaurant windows were smashed, including at businesses crowded with patrons, and demonstrators hurled trash cans at officers, who numbered about 200. Police declared the scene an unlawful assembly and threatened to deploy tear gas, and arrested at least eight people.

"We had been getting such a good turnout earlier and it was a peaceful protest," said Mr Jomar Jackson, 32. "But then a bunch of people came and decided to be disruptive."

Ms Elisheva Heit, whose flower shop window was smashed on the eve of its grand opening, said: "I don't understand how this would bring the poor guy back to life."

Sweeping up glass, she asked passing officers: "This is how you protect people?"

The demonstrations began peacefully last Friday after Circuit Judge Timothy Wilson acquitted former St Louis police officer Jason Stockley, 36, of first-degree murder in the shooting death of Anthony Lamar Smith, 24.

But as of Saturday, Friday's protests ended in late-night violence, with 33 arrests after clashes in which 10 officers were hurt.

"We don't want to see property destruction or see people getting hurt," Mr Elad Gross, a 29-year-old St Louis civil rights attorney, told Reuters as activists gathered peacefully at another protest site in a park on Saturday.

"But this is a protest that addresses injustices not only happening here in St Louis but around the country."

Rock band U2 cancelled a concert scheduled for Saturday in St Louis, and singer Ed Sheeran did the same for his show yesterday, citing security concerns.

"Deeply saddened at what has happened in St Louis and having to cancel our show tonight," U2 singer Bono said in a post on Instagram.

The verdict came about three years after rioting broke out in the St Louis suburb of Ferguson when a black teenager was shot dead by a white police officer.

That incident touched off nationwide soul-searching over law enforcement's use of force against African-Americans, the mentally ill and other groups.

Mr Smith was shot five times in his car after attempting to elude Mr Stockley and his partner, who had chased the suspect after an alleged drug deal, the authorities said.

During the pursuit, Mr Stockley could be heard saying on an internal police car video that he was going to kill Mr Smith, prosecutors said.

Mr Stockley believed that Mr Smith was armed, defence attorneys said, and a gun was found in the car. Prosecutors argued that Mr Stockley planted the weapon and the gun had only Mr Stockley's DNA.

REUTERS