His forces, however, were inadequate to defend an extended line, in addition the water level in the river was very low due to hot and dry summer of 1939, and the advancing Wehrmacht units were able to cross the San without difficulty.

In the evening of that day, members of paramilitary organization Strzelec marched towards Lwów, and on 10 September evacuation of offices of 9th Military District took place.

Due to chaotic situation in the city, army authorities were obliged to use military police to reintroduce order in Przemyśl.

On 10 September in the morning, German 4th Light Division reached the San near Radymno, and after a short skirmish with weak Polish forces, crossed the river.

On 11 September German 2nd Panzer Division reached the area of Przemyśl, chasing Polish 10th Motorized Cavalry Brigade.

On the night of 11–12 September, upon order of General Jan Chmurowicz, Poles attacked German artillery batteries, which were located in Kosienice.

Polish soldiers rested in Przemyśl for a few hours, and in the morning of 14 September marched towards Lwów, leaving behind one infantry battalion with a battery of cannons.

On 14 September in the morning, the Germans tried to capture the city in a frontal attack, but were halted by machine gun fire and artillery.

Main fighting took place in the south, where Germans, after artillery bombardment, crossed the San and attacked the village of Kruhel Maly, which now is a district of Przemyśl.

The four-day battle was followed by three days of massacres carried out by the German soldiers and police against hundreds of Jews who lived in the city.