A GNR patrol unit was surrounded on Saturday night in Olhão by a group of young people, and fired warning shots until PSP backup arrived, said a source from the Professional Guards Association (ASP/GNR). The incident happened after two GNR officers from the Moncarapacho post, in the municipality of Olhão, went to a neighbourhood in the city to return a document that had been found. The incident took place at about 10pm.