As the war progressed Cause_change_of_position_on_a_scale , Armenia and Azerbaijan , both former Soviet Republics , entangled Participation themselves in protracted Change_event_time , undeclared mountain warfare Hostile_encounter in the mountainous heights of Karabakh as Azerbaijan attempted to curb Hindering the secessionist movement in Nagorno-Karabakh .

The wood had dense undergrowth which retarded Hindering movement , made it difficult to keep Preventing_or_letting direction and during the battle the trees were brought Bringing down by shellfire , becoming entangled Hindering with barbed-wire and strewn Filling with German and British dead .