They said officers lacked resources in their fight against the city's criminal organisations.

Hundreds gathered along the seafront in Copacabana to demand more support from the authorities and the population.

Ninety-one police officers have been killed in Rio state this year.

That is more than the total of deaths registered in the whole of 2016.

"I am desperate because I know my husband could be the next one," said Rogeria Quaresma at the march in Rio.

"We see families being destroyed every day. And I don't accept becoming the next widow," she told O Globo newspaper.

In the latest incident, Sgt Hudson Araujo was killed at the Vidigal favela in the early hours of Sunday.

The Brazilian government announced last week it would send an extra 1,000 federal agents to support local police.

'Heinous crimes'

Violence has been on the rise in Brazil - and particularly in Rio de Janeiro - since the end of the Olympics and Paralympics nearly a year ago.

Brazil is now going through the worst recession in its history.

The finances of many states, including Rio, have collapsed and there is no prospect of a solution for Brazil's serious political crisis.

The families of police officers say their loved ones are paying a heavy price for trying to fight crime without the resources and equipment required.

Police officers have been fighting for changes in the penal code so that the killings of police officers are treated as heinous crimes.

They complain that the hard work of honest policemen is not given the same media coverage as alleged human rights abuses in security operations.

In a report published in February, Amnesty International said it was concerned about the growing number of deaths in police operations in Brazil.

More than 800 people were killed by the police in the state of Rio alone in 2016.

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