Four people were arrested in Famagusta district on Monday night, three in relation to a drug case and one for residing illegally in Cyprus.
Famagusta police spokesman Steve Theodoulou said an operation was carried out from 9pm on Monday night till 5am on Tuesday morning, in the framework of combatting serious and organised crime, increasing the sense of safety and trust among residents and cracking down on people residing and working illegally on the island.
The operation included patrols by car and on foot, as well as the setting up of roadblocks.
A total of 21 residents were investigated and a person residing illegally in the republic was arrested and will be deported.
Three people aged 22, 24 and 25 were arrested for possession of drugs.
Theodoulou said police officers also investigated recreation centres. Four were reported for 12 complaints for operating without a licence and without permits for serving drinks and playing music.
Such checks, Theodoulou said, will continue throughout the summer.