# German invasion of Poland and start of WWII

> Live situation record from CLSTR: https://clstr.news/situations/german-invasion-of-poland-and-start-of-wwii
> Updated: 2026-08-31T16:00:00.000Z. Sources: 29. Developments: 2.

The outbreak of World War II was preceded by the Gleiwitz incident, a staged false-flag operation conducted by Nazi Germany as part of ‘Operation Himmler’. Led by SS officer Alfred Naujocks, saboteurs attacked the Gleiwitz radio station and attempted to broadcast a propaganda message in Polish to simulate a Polish takeover. This manufactured provocation was used by Adolf Hitler to justify the invasion of Poland.

On September 1, 1939, Germany launched a military campaign against Poland using Blitzkrieg tactics, including the shelling of Westerplatte and the bombing of Wieluń. The invasion was supported by the Molotov-Ribbentrop Pact, which included a secret protocol for the partition of Polish territory between Germany and the Soviet Union. Following the initial German onslaught, the Soviet Union invaded Poland from the east on September 17, 1939. The conflict resulted in massive casualties, with Poland losing approximately 6 million citizens.

## Claims

- German forces invaded Poland on September 1, 1939 (corroborated by 9 sources)
- The invasion of Poland marked the start of World War II (corroborated by 9 sources)
- The Soviet Union invaded Poland from the east on September 17, 1939 (corroborated by 5 sources)
- Germany and the Soviet Union signed a non-aggression pact on August 23, 1939 (corroborated by 2 sources)
- Germany deployed 1.85 million soldiers during the invasion (corroborated by 2 sources)
- Poland deployed 950,000 soldiers during the invasion (corroborated by 2 sources)
- The German military used Blitzkrieg tactics involving aircraft and tanks (corroborated by 2 sources)
- The Molotov-Ribbentrop Pact included a secret protocol to partition Poland (single source)

## Timeline

### 2026-08-31: Poland invasion: Germany and Soviet Union trigger World War II

The September 1, 1939, German invasion of Poland initiated World War II, characterized by Blitzkrieg tactics and a subsequent Soviet invasion on September 17 following the Molotov-Ribbentrop Pact.

23 sources. https://clstr.news/cluster/poland-the-1939-invasion-and-outbreak-of-wwii

### 2026-08-31: Gleiwitz incident: Nazi false-flag operation used to justify WWII

The Gleiwitz incident was a Nazi false-flag operation in August 1939, where SS saboteurs staged an attack on a radio station to justify Germany's invasion of Poland and the start of World War II.

6 sources. https://clstr.news/cluster/gleiwitz-incident-nazi-false-flag-operation-used-to-justify-wwii

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Cite as: German invasion of Poland and start of WWII. CLSTR, https://clstr.news/situations/german-invasion-of-poland-and-start-of-wwii