Among the troops and commanders, German-Bulgarian relations remained amicable enough. In evacuating the coastal area, Bulgarian artillery units left their immobile pieces in position for German crews to man, and the German liaison officer to the II Corps was allowed to maintain contact with the headquarters of Army Group E. Individuals and small parties outside their respective zones were allowed to return to their units unmolested.
While resigned to the loss of Thrace, the Bulgarian Government, despite the imminent crisis with the Soviet Union, had no intention of relinquishing its status in Yugoslavia. Accordingly, since it lay directly across the main axis of communications between Army Group E and German headquarters for all the southeast at Belgrade, it was necessary for the Germans to make plans to secure Yugoslav Macedonia and southeastern Serbia, the former occupied by the Bulgarian V Corps and the latter by the I Corps. Plan TREUBRUCH assigned the 1st Mountain Division the mission of seizing Skoplje, largest city and rail center of the area; Plan HUNDESSOHN involved the movement of the 4th SS Police Division into Bulgaria in the direction of Sofiya, the capital; Plan JUDAS was the disarmament of the Bulgarian forces in Thrace and Macedonia. Arrangements were made with Army Group F for units of Army Group E to move into its area of responsibility.
While German units prepared for their respective parts in the operations planned in event of hostilities with Bulgaria, fighting with the guerrilla forces increased in intensity. For the 2-month period ending in August, the Germans suffered a total of 936 dead, 1,235 wounded, and 275 missing, meanwhile inflicting casualties on the guerrillas amount to 5,394 dead and 768 captured. Personnel casualties in air attacks on trains, convoys, and troop areas also reached a high during this period, with 32 dead and 26 wounded for the week ending 4 August alone. To improve the air defense of their rail lines and installations, Luftwaffe units were directed to fly high over the railroads and to avoid flying parallel to them. Antiaircraft crews and troops defending the trains and lines were then free to open fire on any aircraft approaching at a low altitude.
The situation by the end of August made it necessary for Army Group E to order the evacuation of all troops in Greece, with the exception of the garrisons of Crete and Rhodes, to the area north of the line Corfu–Yannina–Kalabaka–Olympus. The withdrawal was to be orderly, and measures taken to prevent German intentions becoming known to the Greek population. The troops on railroad security duty were reinforced, and Corps Group Salonika, a provisional organization formed from the administrative command for the Salonika-Aegean area, was merged with an existing skeletal staff to form the
