An angry mum has been caught on camera smacking her son across the head after he starting rioting and throwing rocks at police. The unidentified woman was seen raining blows on her son's head after she found him joining in the protests.

Despite wearing a black ski mask that covered much of his face, the furious mum was able to spot her son. A large crowd can be seen looking on during the brief scuffle, which was captured by American news site WMAR.

In the footage, the woman is seen grabbing a hooded male by his balaclava before hitting him repeatedly over the head.

The incident happened as National Guardsmen fanned out across the city, police with riot shields blocked streets, and firefighters doused smoldering blazes Tuesday after looting and arson erupted in Baltimore following the funeral of a black man who died in police custody.

It was the first time the National Guard was called in to quell unrest in Baltimoresince 1968, when some of the same neighborhoods were convulsed by violence after the assassination of the Rev. Martin Luther King Jr.

The rioting started in West Baltimore on Monday afternoon - within a mile of where Freddie Gray, 25, was arrested and placed into a police van earlier this month - and by midnight had spread to East Baltimore and neighborhoods close to downtown and near the baseball stadium. The streets were calm Tuesday morning.

At least 15 officers were hurt, including six who were hospitalized, police said. There were 144 vehicle fires, 15 structure fires and nearly 200 arrests, the mayor's office said.

Gray's death under still-mysterious circumstances has become the latest flashpoint in the debate across the U.S. over the use of police force against black men.

The rioting was the worst such violence in the U.S. since the turbulent protests that broke out over the death of Michael Brown, the unarmed black 18-year-old who was shot by a white police officer in Ferguson, Missouri, last summer.

Aerial footage Tuesday morning from Baltimore station WJZ-TV showed a firefighter spraying the burned-out shell of a large building.

The city was under a 10 p.m.-to-5 a.m. curfew beginning Tuesday, and all Baltimorepublic schools were closed.

"I understand anger, but what we're seeing isn't anger," Mayor Stephanie Rawlings-Blake lamented. "It's disruption of a community. The same community they say they care about, they're destroying. You can't have it both ways."

State and local authorities pledged to restore order but found themselves responding to questions about whether their initial response had been adequate.

Rawlings-Blake waited hours to ask the governor to declare a state of emergency, and the governor hinted she should have come to him earlier.

"We were all in the command center in the second floor of the state House in constant communication, and we were trying to get in touch with the mayor for quite some time," Gov. Larry Hogan said. "She finally made that call, and we immediately took action."

Rawlings-Blake said officials initially believed they had gotten the unrest under control, "and I think it would have been inappropriate to bring in the National Guard when we had it under control."

But the rioters set police cars and buildings on fire, looted a mall and liquor stores and threw rocks, bottles and bricks at police in riot gear. Police responded occasionally with pepper spray.