A Republic of Congo court on Friday handed jail terms of up to three years to policemen accused of killing 13 young men at a police station in the capital Brazzaville last July.

The head of the station, located in the district of Mpila, was given a two-year sentence and his deputy a three-year term.

Three other policemen were jailed for one year, while a woman police officer, the only female in the group, was handed a 12-month suspended term.

The police had been on trial since October on charges of manslaughter and criminal negligence towards a person at risk.

Around 20 youths had been picked up by police carrying out an "anti-delinquency" operation following a murder in the area.

A campaign group, the Congolese Observatory for Human Rights (OCDH), said the young men had been "tortured and executed" in the police station.

The claim was at first dismissed by Communications Minister Thierry Moungalla, who said the deaths had happened in the street and resulted from clashes between gangs.

Even though the Congolese state, as the employer of the police, admitted legal responsibility, the court of appeal ruled it was not empowered to determine any compensation.

That decision left grieving families in limbo over the loss of a potential wage-earner.

"I have lost my only child," said one tearful mother, who spoke on condition of anonymity.

"He was killed and he would have been sitting for his high-school diploma this year, and the justice says that we won't receive compensation. It makes the pain even worse."

The government has already paid out two million CFA francs (3,049 euros, $3,428) to each family towards funeral costs.