 In addition, the Chief of Staff of the 2nd Panzer Army observed in a letter to the Ustaše liaison officer that the Chetniks fighting the Partisans in Eastern Bosnia were "making a worthwhile contribution to the Croatian state", and that the 2nd Army "refused in principle" to accept Croatian complaints against the usage of these units.German-Chetnik collaboration continued to take place until the very end of the war, with the tacit approval of Draža Mihailović and the Chetnik Supreme Command in the Territory of the Military Commander in Serbia.Though Mihailović himself never actually signed any agreements, he endorsed the policy for the purpose of eliminating the Partisan threat.