XCI Corps headquarters and control units in the Salonika region, through which all forces from the south would have to pass.
On 8 September, Bulgaria declared war on Germany and immediately dispatched strong forces from Sofiya in the direction of the Yugoslav frontier. Lacking the strength to put their ambitious HUNDESSOHN and JUDAS plans into effect, the Germans hurried the 1st Mountain Division to Skoplje, where it operated temporaril under control of the Second Panzer Army, to implement Plan TREUBRUCH. While 5,000 Bulgarians at Bitolj laid down their arms after a brief show of resistance, the garrison at Prilep and Bulgarian units in the Skoplje area fought stubbornly. However, the 1st Mountain Division eventually managed to seize and hold the city of Skoplje and the vital railroad along the Vardar River. Bulgarian units bypassed in the fast German move to the north succeeded in breaking the line at a number of points and had to be driven off by combat groups formed from troops moving northward from Greece to join the 1st Mountain Division.
On the night of 8–9 September, a general rising made it obvious that German units below the line Corfu–Yannina–Kalabaka–Olympus would have to fight their way north. Moving down from the mountains in force, both ELAS and EDES attempted to block the major roads and railways to the north. In western Greece, troops of the XXII Mountain Corps had to fight hard to keep the Arta–Yannina road open in order to evacuate the Cephalonia garrison and units in southwestern Greece. In eastern Greece, the LXVIII Reserve Corps, having already lost its 11th Luftwaffe Field Division to the defense of Macedonia, managed to regain long stretches of the rail line to Salonika only after a series of seesaw actions with strong ELAS units.
To reinforce the units already heavily engaged in the north and threatened by an estimated three Bulgarian armies moving west to cut off the withdrawal of Army Group E, General Loehr directed an airlift of combat troops from Crete and Rhodes. A total of 11,500 men evacuated from Crete alone in this operation, most of them from the 22d Airborne Division, proved to be a substantial addition to the hard-pressed units north of Salonika. However, fighter aircraft from Allied carriers now operating in force in Greek waters made impossible the completion of the airlift. As of 12 October, some 26,500 service and combat troops were still stranded on Crete, Rhodes, and other German-held islands, with little or no prospect of escape. Instructed to fight to the end and destroy all installations and materiel of value to the enemy, the bulk of these troops, representing all three services, were left to their fate.
