OAU Convention on the Prevention and Combating of Terrorism, 1999 (commission rogatoire) relating to a terrorist act shall not be rejected on the grounds of the principle of confidentiality of bank operations or financial institutions, where applicable. Article 17 The States Parties shall extend to each other the best possible mutual police and judicial assistance for any investigation, criminal prosecution or extradition proceedings relating to the terrorist acts as set forth in this Convention. Article 18 The States Parties undertake to develop, if necessary, especially by concluding bilateral and multilateral agreements and arrangements, mutual legal assistance procedures aimed at facilitating and speeding up investigations and collecting evidence, as well as cooperation between law enforcement agencies in order to detect and prevent terrorist acts. PART VI FINAL PROVISIONS Article 19 1. This Convention shall be open to signature, ratification or accession by the Member States of the Organization of African Unity. 2. The instruments of ratification or accession to the present Convention shall be deposited with the Secretary General of the Organization of African Unity. 3. The Secretary General of the Organization of African Unity shall inform Member States of the Organization of the deposit of each instrument of ratification or accession. 4. No State Party may enter a reservation which is incompatible with the object and purposes of this Convention. 5. No State Party may withdraw from this Convention except on 217