ðɪ ɪntˈɜːnəl sᵻkjˈʊɹɹᵻɾi jˈuːnɪt ˌaɪˌɛsjˈuː wʌzðə kˈaʊntɚɹɪntˈɛlɪdʒəns ænd ɪntˌɛɹəɡˈeɪʃən jˈuːnɪt ʌvðə pɹəvˈɪʒənəl ˈaɪɹɪʃ ɹᵻpˈʌblɪkən ˈɑːɹmi ˌaɪˌɑːɹɹˈeɪ.
The Internal Security Unit (ISU) was the counter-intelligence and interrogation unit of the Provisional Irish Republican Army (IRA).