The presence of mercenaries or private armies in conflict zones around the world is nothing new to the international community. This is evident from the unlawful operations of a US based private military company Blackwater, also known as Xe, in Iraq, Afghanistan and now in Pakistan. However, the situation becomes more interesting when the presence of Blackwater (as per media reports) has been witnessed in Pakistan, as part of the covert operations to target Taliban and Al-Qaeda operatives in the region. Such reports have indeed triggered public anger fuelling anti-American sentiments. Private security companies, like Blackwater, have become one of the hallmarks of modern warfare. Their legal status is obscure, discipline is sporadic and accountability is sparse. Thus, the increasing role of mercenaries in contemporary wars highlights the need to review the existing international legal system. The International Humanitarian Law comprising of the four Geneva Conventions of 1949 and their Additional Protocols (AP) I and II of 1977 are the effective legal instruments for "the protection of victims of armed conflict." Under Article 47 of AP-I, mercenaries are defined as people (local or foreigners) who are specially recruited to fight in an armed conflict and are motivated by the desire for "private gain". The International Convention against the Recruitment, Training, Financing and Use of Mercenaries 2001, identifies mercenaries in similar terms as Article 47 of AP-I 1977, and further includes concerted acts of violence for overthrowing the government or for undermining the territorial integrity of a state. In this context, there is a need to regulate the functions and activities of these private security companies. This is mainly derived from two concerns. Firstly, these personnel do not abide by the established legal regimes to maintain discipline and respect for human rights. Secondly, their actions are not subject to public scrutiny. Arguments maybe proposed under the ambit of customary international law, which are embodied in the form of the International Law Commission (ILC) Draft Articles on State Responsibility, 2001. According to this law, if an international obligation has been breached, an action maybe sought against the State. It is also imperative to note that a number of legal instruments exist in the domestic laws of the US, which aim to achieve accountability in the private military industry. They include the Arms Export Control Act 1968 (AECA) which regulates the dealing and sales of military service. Moreover, the International Traffic in Arms Regulations not only implements the AECA, but requires any company offering military services or advice to foreign nationals abroad, needs to obtain license from the US State Department. Being mindful of the above analysis, it is imperative to note that a plethora of contracts and licenses bind these security companies or private armies to their employers, their host and home States. As State agents, they carry its reputation and obligations. In situations where an effective mechanism of control and accountability is absent, the possibility of grave human right abuse increases. While it is plausible to lament on the lack of direct legal obligations on the security companies under the international law, it is essential to note that States must be held accountable due to their status as fundamental actors under the international law. The writer is a lawyer and a research associate at the Research Society of International Law, Pakistan. Email: aaleengardezi@rsilpak.org