The plan
For months prior to the 1939 invasion, German newspapers and politicians like Adolf Hitler had carried out a national and international propaganda campaign accusing Polish authorities of organizing or tolerating violent ethnic cleansing of ethnic Germans living in Poland.
The plan, named after its originator, Heinrich Himmler, was supervised by Reinhard Heydrich and managed by Heinrich Müller. The goal of this false flag project was to create the appearance of Polish aggression against Germany, which could be used to justify the German invasion of Poland. Hitler also might have hoped to confuse Poland's allies, the United Kingdom and France, into delaying or stopping their declaration of war on Germany.
"I can no longer find any willingness on the part of the Polish Government to conduct serious negotiations with us. These proposals for mediation have failed because in the meanwhile there, first of all, came as an answer the sudden Polish general mobilization, followed by more Polish atrocities."
from CNN
Russia complains of large Ukrainian troop buildup in east
A perilous faceoff intensified Saturday when Russia state news complained that Ukraine had mobilized 15,000 troops in the suburbs of Slavyansk in eastern Ukraine "in order to wipe out the city and its residents."
From Wiki - Slavyansk population - 116,490.
Hopefully, history isn't going to repeat itself.