▁Part isan ▁withdraw al ▁ ▁Although ▁its ▁total ▁strength ▁was ▁estimated ▁at ▁ 1 8 5 , 5 0 0 ▁men ▁in ▁late ▁May ▁ 1 9 4 4 , ▁the ▁ 2 nd ▁Pan zer ▁Army ▁was ▁not ▁able ▁to ▁r ally ▁more ▁than ▁ 1 6 , 0 0 0 ▁troops ▁for ▁Operation ▁Rö ss els pr ung ▁due ▁to ▁ever - in cre asing ▁Part isan ▁activity ▁throughout ▁the ▁country . ▁The ▁Germ ans ▁had ▁to ▁rely ▁on ▁special ▁forces ▁and ▁improved ▁tact ics . ▁The ▁Part is ans ▁def ended ▁the ▁territory ▁they ▁controlled ▁with ▁significant ▁demol ition ▁and ▁min ing ▁of ▁roads . ▁Road block s ▁were ▁man ned ▁by ▁pat rol s ▁and ▁smaller ▁det ach ments , ▁whose ▁task ▁was ▁to ▁hold ▁off ▁the ▁enemy ▁until ▁rein for c ements ▁arrived . ▁During ▁Operation ▁Rö ss els pr ung , ▁the ▁Germ ans ▁rendered ▁these ▁tact ics ▁in effect ive ▁by ▁combining ▁strong ▁and ▁fast ▁motor ised ▁columns ▁with ▁ade qu ate ▁pione er ▁support . ▁This ▁combination ▁was ▁especially ▁successful ▁for ▁the ▁column ▁led ▁by ▁the ▁ 9 2 nd ▁Motor ised ▁Regiment . ▁The ▁second ▁German ▁tact ical ▁innov ation ▁was ▁the ▁employ ment ▁of ▁five ▁reconna issance ▁batt al ions ▁for ▁independent ▁operations ▁deep ▁inside ▁Part isan - control led ▁territory . ▁▁ 2 5 ▁May ▁Through out ▁ 2 5 ▁May , ▁the ▁ground ▁forces ▁of ▁XV ▁Mountain ▁Corps ▁were ▁not ▁able ▁to ▁advance ▁as ▁quickly ▁as ▁planned . ▁There ▁was ▁unexpected