(1) Subject to subsections (2) to (4), a person is guilty of an offence if the person -

(a) in or outside the State -

(i) engages in a terrorist activity or a terrorist-linked activity,

(ii) attempts to engage in a terrorist activity or a terrorist-linked activity, other than public provocation to commit a terrorist offence, or

(iii) makes a threat to engage in a terrorist activity,

or

(b) commits outside the State an act that, if committed in the State, would constitute -

(i) an offence under section 21 or 21A of the Act of 1939, or

(ii) an offence under section 6 of the Act of 1998.

(2) Subsection (1) applies to an act committed outside the State if the act -

(a) is committed on board an Irish ship,

(b) is committed on an aircraft registered in the State,