The Montreux Document is a multinational agreement specifying governance practices regarding private military and security companies in war zones.
[1] Its full name is "The Montreux Document on Pertinent International Legal Obligations and Good Practices for States Related to Operations of Private Military and Security Companies During Armed Conflict".
The document lists some 70 recommendations for state practices such as verifying company track records, examining procedures used to vet staff, conduct prosecution when breaches occur, and ensure compliance and personnel training compatible with international humanitarian and human rights law.
It is a non-binding, non-legal document in that it neither creates nor alters legal obligations, but articulates existing requirements pertinent to private security operations.
[3] This document states that governments take responsibility in these situations: Elements have been incorporated into the management system standards jointly authored and published by ANSI/ASIS, such as PSC.1-2012 and PSC.4-2013.