Introduction: The Phenomenon of Foreign Fighters and Foreign Terrorist Fighters An International Law and Human Rights Perspective

Modern international law defines a very narrow definition of mercenarism. It does not include all aspects of this phenomenon as it was known and understood for centuries. At the same time the emergence of new forms of mercenary-related activities is observed. The terms 'foreign fighters' and 'foreign terrorist fighters' should be analysed in this context inter alia from a legal perspective. A question needs to be answered if those existing regulations relating to mercenaries can apply to these terms. It is also important to note how both mercenaries and their activities are perceived under international law. The international legal analysis of factual and legal measures undertaken by states towards foreign fighters and foreign terrorist fighters is also interesting. Frequently these activities concern not just the fighters alone but apply also to all of us. This requires us to look at them in the context of international human rights law. These issues are the subject of current works undertaken within the scope of international organisations. UN Security Council adopted resolution 2170 (2014) and 2178 (2014) regarding foreign terrorist-fighters. The UN General Assembly and UN Human Rights Council also tackle these issues. The activity of foreign fighters and foreign terrorist fighters on one side and the activities of the states in reaction to this activity on the other side are also monitored inter alia by the UN Working Group on the use of mercenaries.