Rufino Antonio died after the military opened fire in August 2016 at a demonstration against the demolition of houses for an industrial project in Zango, a working class suburb on the outskirts of the capital Luanda.

Witnesses said the soldiers fired without warning into the air and at protesters' feet to disperse the crowd, with Antonio shot fatally in the neck in an incident that caused widespread anger in Angola.

The judge at the court in Luanda sentenced Jose Alves Tadi, who was found guilty of the killing, to 18 years in jail and ordered him to pay 1,000,000 kwanza ($3,700) to the boy's family.

"We hope today's verdict and sentence will send a clear message that nobody is above the law in Angola," Zenaida Machado, Angola specialist at Human Rights Watch, told AFP.

Family lawyer Luis Nascimento confirmed the sentences, but called for higher compensation.

Three other soldiers were sentenced to one year in jail.