In the midst of the attacks, many Armenians sought to defend themselves and improvised by nailing their doors shut and arming themselves with axes, and in some instances a number of intruding rioters were killed. Calls to ambulance services were handled late or in many cases, unheeded completely. There was no intervention on the part of the police to stop the perpetrators. As mentioned by De Waal, "Another factor, which seems to have been a necessary condition for ethnic violence to begin, came into play: the local police did nothing. It later transpired that the local police force was overwhelmingly composed of Azerbaijanis and had only one professional Armenian officer."