1. Each State Party shall take such measures as may be necessary to establish its jurisdiction over the offences referred to in Article 4 in the following cases:
(a)When the offences are committed in any territory under its jurisdiction or on board a ship or aircraft registered in that State;
(b)When the alleged offender is a national of that State;
(c)When the victim is a national of that State if that State considers it appropriate.
2. Each State Party shall likewise take such measures as may be necessary to establish its jurisdiction over such offences in cases where the alleged offender is present in any territory under its jurisdiction and it does not extradite him pursuant to Article 8 to any of the States mentioned in paragraph 1 of this article.
3. This Convention does not exclude any criminal jurisdiction exercised in accordance with internal law.