[1] That made Army Pomorze, under General Władysław Bortnowski, find itself in the Polish Corridor while it was surrounded by German forces on two fronts.

[12] By 8 September, Kutrzeba had lost contact with Rydz-Śmigły, who had relocated his command center from Warsaw to Brest.

[13][14][17] The cavalry brigades, supplemented with TKS and TK-3 reconnaissance tanks, moved to threaten the flanks and the rear of the advancing German units.

[18] The German forces were thrown back approximately 20 km, and the Poles recaptured several towns, including Łęczyca and Piątek, and the village of Góra Świętej Małgorzaty.

[19] German air superiority had a significant impact by making it very costly and difficult for the Poles to move units during the day.

That day, General Tadeusz Kutrzeba learned that units of Army Łódź had retreated to the Modlin Fortress and decided to stop the offensive and instead sought to try to break through Sochaczew and the Kampinos Forest to reach Warsaw.

[14][19] On the morning of 14 September, General Władysław Bortnowski's 26th and 16th Infantry Divisions crossed the Bzura near Łowicz.

To encircle and to destroy the Polish forces, the Germans used most of their 10th Army, including two armoured, one motorized and three light divisions, which was equipped with some 800 tanks altogether.

[20] On 17 September, German heavy artillery was shelling the crossing north of Brochów, and the largest air operation of the campaign began, with the Luftwaffe attacking the retreating Polish forces.

In the morning, the Germans started their drive towards the south along both banks of the Bzura and were supported by more than 300 aircraft and heavy artillery.

[20] After two days of heavy fighting, with no ammunition or food rations remaining, further attempts at a breakout for the Poles became impossible.

[20] The groups crossed the Kampinos Forest and fought German units in the area (such as at the Battle of Wólka Węglowa), then entered Warsaw and Modlin, mostly around 19 and 20 September.

[2][14] Polish casualties were estimated at 20,000 dead, including three generals: Franciszek Wład, Stanisław Grzmot-Skotnicki and Mikołaj Bołtuć.

The Bzura campaign ended in defeat for the Poles, but because of the initial Polish local successes, the German advance on Warsaw was halted for several days.

[23] That helped the Polish units defending Warsaw and its environs to organise their own long-term but ultimately failed defence of the capital.