Battle of Mokra 

On September 1, at 0500, the German Tenth Army of Army Group South crossed the Polish border and initiated the invasion of Poland. The German 31st Infantry Division, as well as 1st and 4th Panzer Divisions crossed the border in the operational sector of the Polish Volhynian cavalry brigade. After breaking through small detachments of the Border Guard and National Defence, the German units seized the towns of Krzepice and Starokrzepice, right in front of the main Polish positions. After capturing them, the Germans razed both towns and expelled all inhabitants towards the Polish lines.

The German units were divided into three separate assault groups. The 1st Panzer Division headed directly towards the town of Kłobuck, held by the Polish 7th Infantry Division, while the 4th Panzer Division was split into northern and southern columns, each trying to outflank the Polish positions around Mokra. At the same time, the Luftwaffe started a heavy bombardment of the Polish positions. All together by the end of the day, German air raids arrived 15 times, with between 9 and 26 bombers each. The airplanes used were mostly Junkers Ju 87 Stuka dive bombers.

At 0630 in the morning the motorcycle reconnaissance squads of the 4th Panzer Division made contact with the 12th company of the 84th Infantry Regiment under Stanisław Radajewicz. Soon afterwards the AFVs arrived, supported by infantry and purportedly using civilians as human shields.[citation needed] However, after several shots from the sides, the German tanks lost orientation, which allowed for the civilians to cross the Polish lines with negligible losses. The German assault was renewed shortly afterwards, but was repelled by heavy machine gun fire. Two AFVs retreated, while the majority of the motorcyclists were taken prisoner.

The 4th Panzer Division then mounted an assault on the Polish 21st Uhlans Regiment, further northwards. After a short artillery barrage and aerial bombardment, the German tanks took the v...

The German 4th Panzer Division was forced back to its initial positions in Opatów and Wilkowiecko, and only the 12th Schützen Regiment managed to reach the rail road crossing at Izbiska. However, upon learning that the German 1st Panzer Division had managed to take Kłobuck, the Polish forces were withdrawn overnight south-eastwards, to the village of Łobodno located north-east of Kłobuck, and then to the second line of defence, some 12 km to the east.