Related Rule
Portugal
Practice Relating to Rule 161. International Cooperation in Criminal Proceedings
Section C. Extradition of own nationals
Portugal’s Law on International Judicial Cooperation in Criminal Matters (1999), as amended in 2001, provides:
1. Extradition shall be excluded … in the following cases:
a) where the offence was committed on Portuguese territory;
b) where the person claimed is a Portuguese national, without prejudice to the provisions of the following paragraph.
2. The extradition of Portuguese nationals shall however not be excluded where:
a) extradition of nationals is provided for in a treaty, convention or agreement to which Portugal is a Party, and
b) extradition is sought for offences of terrorism or international organized crime, and the legal system of the requesting State embodies guarantees of a fair trial. 
Portugal, Law on International Judicial Cooperation in Criminal Matters, 1999, as amended in 2001, Article 32.