The police on Monday arrested 13 people who were found to be illegally residing and working in Malta.
In a statement, the police said detention services officers and Occupational Health and Safety Authority officials carried out inspections at construction sites in St Paul's Bay on Monday morning.
A total of 13 people - from Georgia, Albania, Pakistan, Mali, Senegal and Nigeria - were taken to the Floriana police headquarters to start the deportation process.
Police investigations are ongoing.