The main purpose of the attack was to capture the Jablunkov Pass, with its strategic railway tunnel, until the arrival of the German armed forces.

[3] Part of Germany's plan to invade Poland, Fall Weiss (Case White), involved small groups of Germans dressed in Räuberzivil ("robbers' civvies" - inconspicuous, rugged casual clothing) crossing the border the night before and seizing key strategic points before dawn on the day of the invasion.

The secret Abwehr battalion detailed to undertake these operations was given the euphemistic title of "Construction Training Company 800 for Special Duties".

In October 1938, together with the territory of Trans-Olza, it was annexed by the Second Polish Republic; therefore, Poland controlled a key railroad connection, the Košice-Bohumín railway line.

[7] The task of the Abwehr detachment under Herzner was to capture both the rail station at Mosty and the strategic tunnel to prevent its destruction by Polish forces.

[citation needed] The German detachment of some 70 agents dressed in civilian clothes (some sources put the number at 24),[9] set off from Čadca on 25 August late in the evening.

During the night, they crossed the Polish-Slovak border near the mountain of Velký Polom and reached the station at Mosty at around 04:00 on 26 August unaware that Hitler had cancelled his order and delayed the attack on Poland until 1 September.

In the following minutes, the Germans captured the station after some fighting, and took prisoner a group of workers on their way to the Třinec Iron and Steel Works.