RIO DE JANEIRO -- Authorities confirmed Monday that 34 people were shot dead over the last three days in the Brazilian city of Manaus, capital of the state of Amazonas.

While admitting the body count over the weekend was " unacceptable" and the "situation had become grave," Attorney General of Amazonas Fabio Monteiro stopped short by saying at a press conference that the police believed the killings were committed by a certain criminal group.

No more information as for factors such as the perpetrators of the murders and reasons behind the killings is available at the moment.

Police is investigating into the violence.