2. Each
State Party may take such
measures as may be necessary to
establish its
jurisdiction over the
offences referred to in
article 3, paragraph 1, in the following
cases:
3. Each
State Party shall also take such
measures as may be necessary to
establish its
jurisdiction over the aforementioned
offences when the alleged
offender is present in its
territory and it does not
extradite him or her to another
State Party on the ground that the
offence has been committed by one of its
nationals.