An unlimited right of non-self-incrimination of witnesses before international criminal tribunals exists only during the pre-trial investigation (Article 55 ICC Statute); during trial the right is not unlimited, as the witness can be compelled to answer any question, either on the basis of an ex ante assurance of non-use of the evidence against him/her coupled with an assurance of confidentiality (ICC Rule 74(3)(c)) or on the basis of a guarantee of non-use without an explicit assurance to that effect (ICTY/ICTR Rules 90(F)). It is doubtful whether these rules are compatible with the principle nemo tenetur se ipsum accusare since this principle protects not only the accused but also the witness from a criminal prosecution which is based on her own statements.