Immigration detention is the policy of holding individuals suspected of visa violations, illegal entry or unauthorized arrival, as well as those subject to deportation and removal until a decision is made by immigration authorities to grant a visa and release them into the community, or to repatriate them to their country of departure. Mandatory detention refers to the practice of compulsorily detaining or imprisoning people seeking political asylum, or who are considered to be illegal immigrants or unauthorized arrivals into a country. Some countries have set a maximum period of detention, while others permit indefinite detention.