of remaining vigilant against practices that erode the absolute prohibition of torture in the context of counter-terrorism.68 States’ international responsibility may be engaged for committing an internationally wrongful act, for bringing assistance or aid to other States in the commission of a wrongful act, for acquiescing in this conduct or for failing to prevent such acts from occurring on its territory. States may also be held responsible when their agents have acted ultra vires. In addition, where such violations have taken place, States have a duty to undertake prompt and effective investigations to identify and prosecute those responsible, as well as ensure that the victims are adequately compensated.69 D.  Liberty and security of the person All persons are protected against the unlawful or arbitrary interference with their liberty. This protection is applicable in the context of criminal proceedings, as well as other areas in which the State might affect the liberty of persons.70 In practice, as part of their efforts to counter terrorism, States have adopted measures which have an impact on the liberty of persons, such as: pretrial procedures for terrorism offences, including provisions concerning bail and the remand of persons in custody awaiting trial; pretrial detention (detention before laying a criminal charge against a person for the purpose of further investigating whether that person was involved in the commission, or assisted in the commission, of a terrorist offence); administrative detention (detention to prevent a person from committing, or assisting in the commission of, a terrorist offence); control orders (imposing conditions on a person, short of detention, to prevent that person from committing, or assisting in the commission of, a terrorist offence, including the detention of a person awaiting determination of immigration or refugee status); and compulsory hearings (detention and compulsory questioning of a terrorist suspect, or non-suspect, to gather intelligence about terrorist activities). As part of its efforts to counter terrorism, a State may lawfully detain persons suspected of terrorist activity, as with any other crime. However, if a measure involves the deprivation of an individual’s liberty, strict compliance with international and regional human rights law related to the liberty and security of persons, the right to recognition before the law and the right to due process is essential. Any such measures must, at the very least, provide for judicial scrutiny and the ability of detained persons to have the lawfulness of their detention determined by a judicial 36