Tomaszów Lubelski — Piskor between 2 fronts

In mid-September 1939, after the defeat on the Bzura, the surviving elements of several Polish armies (Army Krakow under General Antoni Szylling, Army Lublin under General Tadeusz Piskor, remnants of Army Małopolska under General Kazimierz Fabrycy) attempt to reach the "Romanian bridgehead" — an organized withdrawal toward the south-east in the direction of the Romanian border, to preserve forces for reconstitution abroad.

By 17 September, these forces — about 65,000 men and 120 guns — are concentrating in the region of Tomaszów Lubelski, 60 km north of the Romanian border. Marshal Rydz-Śmigły orders Piskor by radio to "break through" to the south. But on the same night, the Soviet invasion of 17 September cuts the road to Romania. The Polish pocket is now caught in a pincer between List's 14th German Army (advancing from Slovakia) and Timoshenko's Soviet forces (pushing from the east).

Piskor must choose between breaking through to the south (Romania) across the German 14th Army, breaking through to the south-east (Hungary via the Bieszczady border) across the German 7th Armoured Corps, or holding his ground to fix enemy forces, with no hope of tactical salvation.

From 18 to 20 September, first battle of Tomaszów Lubelski: the Krakow-Lublin army tries to break through to the south. Fierce combat at Krasnobród (cavalry charge by the Polish 25th Wielkopolski Regiment on 23 September), Tomaszów, Cześniki, Susiec. The German forces — 4th Light Infantry Division, 2nd Panzer Division, 27th Infantry Division — block the breakthrough.