1. Each State Party shall take such measures as may be necessary to establish its jurisdiction over any of the offences set forth in the present Convention which are committed :

(a) In its territory or on board a ship or aircraft registered in that State;

(b) By any of its nationals or, if that State considers it appropriate, by those stateless persons who have their habitual residence in that territory.

2. Each State Party shall likewise take such measures as may be necessary to establish its jurisdiction over the offences set forth in articles 2, 3 and 4 of the present Convention in cases where the alleged offender is present in its territory and it does note extradite him to any of the States mentioned in paragraph 1 of this article.

3. The present Convention does not exclude any criminal jurisdiction exercised in accordance with national law.