The international humanitarian law contains many provisions relating to the situation of people deprived of their freedom.

In International armed conflicts, the following persons are protected by the Geneva Conventions of 1949 and Additional Protocol I thereto:

• prisoners of war, by the Third Geneva Convention which is devoted entirely to them (for instance, during the Gulf War, Iraqi prisoners detained by the Coalition forces and prisoners from Coalition countries in the hands of Iraq);
• civilian internees (i.e. civilians deprived of their freedom as a precaution for security reasons), by the Fourth Geneva Convention of 1949 on the protection of civilians in wartime (for instance Iraqi nationals living in the United Kingdom, Italy and France and interned there from the start of the Gulf War);
• in the event of territorial occupation, persons suspected or accused of committing acts hostile to the occupying power, persons tried for such acts and penal law prisoners, by the provisions of the Fourth Geneva Convention (for instance, Palestinians detained or interned by Israel).

The States party to the Geneva Conventions have formally undertaken to allow ICRC delegates to visit the aforesaid persons in the event of international armed conflict.

In non-international armed conflicts, on the other hand, people who are not or are no longer taking part in the hostilities, particularly those deprived of their freedom, are protected by Article 3 common to the Geneva Conventions and by Additional Protocol II.

The ICRC steps in on their behalf by virtue of the right of initiative assigned to it by the Conventions. In practice, it draws on the concepts applicable to international armed conflicts to define the categories of prisoners to whom it wants access: members of government armed forces, armed rebels captured by enemy forces, and civilians arrested by the government or the armed opposition on grounds of their real or presumed support for the other side. The ICRC likewise visits people who are likely to be persecuted because of their ethnic origin.

The ICRC may also offer its services to the authorities in the event of internal unrest, as in South Africa during apartheid or in Romania following the fall of the Ceaucescu regime. In such cases it acts, according to the gravity and urgency of the humanitarian needs observed, on the basis of the humanitarian right of initiative laid down in the Statutes of the International Red Cross and Red Crescent Movement and accepted by the States. For its detention-related activities those two criteria are determined by factors such as the number of arrests, the effectiveness of supervisory mechanisms within the country, the conduct of police and security forces and allegations of ill-treatment and disappearances. Then again, the ICRC may offer its services to the authorities in other situations such as serious disruptions of law and order or the lack of minimum guarantees of individual safety, for instance, if many people are affected or if it believes that its intervention may reduce tension.

Over the years the ICRC has steadily extended the scope of its activities: criminal law offenders are included in its representations and visits if they share the same premises as persons arrested in connection with civil unrest, or if they are suffering as a direct result of that situation. For example, if prison food supplies are inadequate (thus affecting all prisoners, regardless of their status or the reasons for their arrest), the ICRC asks the authorities to take the necessary steps to remedy the shortage. Any additional assistance provided by the ICRC is distributed to all prisoners alike.