During the relentless fighting that followed, Allied forces suffered a high rate of attrition and were unable to keep up with the level of damage being sustained. Of the M.S.406s that saw action against the Germans, heavy losses were incurred; reportedly, 150 aircraft were lost in action while a further 250–300 fighters were recorded as having been lost through other causes. The rapid advance of German forces led to repeated retreats and abandonment of bases, rendering most repair and replacement efforts disorganized, along with ground crews often having to destroy large numbers of their own fighter aircraft on the ground to prevent their capture. The decision to employ small groups of French fighters against larger German formations was mostly ineffective against bombers and often costly.