The first part is from Russian social media. The rest is the experience of my father.

The Germans forced us to dig a pit. When the pit was ready, they lined us up. A German officer said, "Jews, step out!" The Jews stepped out. "Jews, jump into the pit!" The Jews jumped. "Russians, grab your shovels and bury the Jews!" We looked at each other, and no one picked up their shovels. The German said, "Jews, get out!" "Russians, jump into the pit!" "Jews, bury the Russians!" The Jews grabbed their shovels and began burying us. When the earth reached our waists, the German stopped the Jews and asked, "Well, Russian, do you understand who the Jews are?" 1941, a prisoner of war story...

The story is believable at least in part.

This was a common practice with the Japanese during WWII.
My own father was a prisoner of the Japanese during the war. He was interned first at Santo Tomas and after two years he was moved to Los Banyos which was across Manila Bay from Manila.
One day the guards took all the ambulatory prisoners outside the camp and gave them shovels and ordered them to dig. 🪏
They dug a trench two meters deep, two meters wide and over fourty meters long.
Everyone knew what it would likely be used for. It was just the perfect size to bury all the prisoners in the camp over six feet underground.
The next morning, there was quite a commotion. Philippino gorillas rushed out of the jungle, shooting at the guards, who were doing morning exercises.
Planes flew over and dropped 11th Airborne paratroopers into the camp.
Soon Amtraks arrived and took the frail prisoners away.
The soldiers set the buildings on fire in order to motivate the rest of the prisoners to get moving.
They all walked down to the beach where the amtraks returned and evacuated everyone.
If they hadn’t been rescued when they were they would all have been shot in the bottom of that trench.