Twenty-eight people found to be living in Malta illegally were apprehended by police during inspections in Ħamrun on Saturday evening.
The police said the inspections were tied to irregular migration and irregular commercial activity.
Officers carried out inspections in public spaces, service shops and grocery shops, as well as in several private residences throughout the island, the police said in a statement on Sunday.
Those detained were from Syria, Nepal, Mali, Ghana, Nigeria and Burkina Farso. They will be held in a detention centre until being returned to their country of origin or an alternative country where they can reside, the statement read.
The police, together with labour and tax authorities, are also investigating the shops in which searches were made in relation to abuse of labour or trade laws and rules.
Assisting the police were officers from the Detention Services Agency and the enforcement unit of the Malta Tax and Customs Administration.
The statement said coordinated work in "various fields" will continue in the coming days and weeks.