CYIL 7 ȍ2016Ȏ ISLAMIC STATE, AN ACTOR THREATENING PEACE IN THE MIDDLE EAST without the agreement of the respective state governments against the suspected terrorists in Somalia and in Pakistan. 61 Russia reacted to the USA air strikes in Syria with a statement which describes them as contradictory to international law. The Russian minister of foreign affairs stated that air strikes are only permissible by international law with explicit consent of the Syrian government or by a relevant resolution of the UN Security Council. 62 Also Turkey claims the right to self-defence in the sense of Article 51 of the UN Charter both against the Islamic state, like the USA, and against the Kurdistan Workers’ Party (PKK) which operates on the territory of Syria. 63 Turkey is claimed to have conducted about 500 attacks against the Kurdistan Workers’ Party (PKK) and Kurdish militia who were active on the territory of Syria in August 2015, but only 3 attacks against the Islamic state. 64 It is questionable, however, whether the right to self-defence is legal in case the state from whose territory the attack stems is unwilling or unable to prevent such an attack. This argumentation has been used by the USA in several cases, especially in justifying their intervention in Afghanistan in 2001. In this case the intervention of the USA was in a way supported by UN Security Council Resolution No. 1267/1999, which requires the Afghan Taliban to cease its provision of sanctuary and training for international terrorists and their organizations and take appropriate effective measures to ensure that the territory under its control is not used for terrorist installations and camps. The concept of unwillingness or inability has been used by the USA in other cases against suspected terrorists – for example in the above mentioned cases in Somalia and Pakistan. 65 In this relation it is worth mentioning that the concept of unwillingness or inability is considered by the legal doctrine which examines what support of terrorist activity is. P. Starski, for example, mentions that support of terrorist activity is not uniform and can be compared to a cascade of different levels of state participation. 66 She distinguishes nine levels of involvement, from express support in the form of financing and delivery of weapons to such cases which can be described as unwillingness or inability. The fifth level is when the state tolerates these activities by remaining passive or refrains from prosecuting the perpetrators. Another level is when the state just fails to prevent a specific attack or to prosecute the offenders in its aftermath out of mere (negligent) ignorance. The seventh level is incapacity; the eighth is when they might not take counteraction against terrorist activities in 63 STARSKI, Paulina. Right to Self-Defense, Attribution and the Non-State Autor- Birth of the “Unable or Unwilling” Standard? Zeitschrift fur auslandisches offentliches Recht und Volkerrecht , 2015, Vol. 75, p. 500. 64 Ibid . 65 CONTEMPORARY PRACTICE OF THE UNITED STATES. United States Deepens Its Engagement with ISIL Conflict. American Journal of International Law , 2015, Vol. 109, No. 1, p. 204. 66 supra n. 63, p. 459. 61 Ibid ., p. 204. 62 Ibid ., p. 206.