 In addition, an armoured battalion was added to the 622nd Mechanised Brigade, and a mechanised battalion to JNA garrisons in Vinkovci and Vukovar each in May 1991.Likewise, Croatian forces were strained between maintaining the blockade and manning the positions held against the JNA and Croatian Serb militias elsewhere.Surrendered JNA troops were either transported to Serbia, exchanged for prisoners of war captured elsewhere, or were given civilian clothing and released.