Portugal declares that it will authorise extradition of Portuguese nationals from national territory only under the conditions laid down in the Constitution of the Portuguese Republic: (a) in cases of terrorism and international organised crime; and (b) for the purposes of prosecution, provided that the requesting State guarantees the extradited person’s return to Portugal, to serve the sentence or penalty imposed unless that person expresses his opposition by an explicit declaration. For the purposes of carrying out the sentence in Portugal, the procedures set out in the declaration made by Portugal in connection with the Council of Europe Convention on the Transfer of Sentenced Persons shall be observed.