Ivan Martynushkin, a senior lieutenant in the Soviet Army, had just turned 21 when the gunner unit he commanded was ordered to advance toward the Polish town of Oswiecim.
His unit, part of the Red Army's 322nd Rifle Division, repeatedly battled German troops as they slowly moved southwest from a newly liberated Krakow. Tired and anxious, he says his soldiers had no idea what to expect next.
"We beat back the Germans in one village, passed through, and came out onto some kind of enormous field almost completely surrounded by electrified barbed-wire fences and watchtowers," says Martynushkin, now a dignified-looking 91-year-old.
"We saw buildings beyond the barbed wire. And as we got closer, we began to see there were people."
The people, Martynushkin would soon discover, were prisoners -- Poles, Jews, Roma, and other minorities facing almost-certain extermination at Nazi Germany's most notorious death camp.
An estimated 1.1 million prisoners died at the Auschwitz prison complex, suffocated in gas chambers or killed by the combined effects of starvation, heavy labor, torture, and disease.
By the time Red Army units arrived at Auschwitz, just over 7,500 people remained at the camp.
Martynushkin says it was not immediately apparent who the people were.
"At first there was wariness, on both our part and theirs," he says. "But then they apparently figured out who we were and began to welcome us, to signal that they knew who we were and that we shouldn't be afraid of them -- that there were no guards or Germans behind the barbed wire. Only prisoners."
Martynushkin's unit did not immediately enter the camp -- that task was the responsibility of the 100th and 107th divisions of the 60th Army of the First Ukrainian Front.
'We Had Done Something Good'
Instead, the gunner unit paroled the territory surrounding the camp, searching for hidden patches of German soldiers. Once the area was secure, Martynushkin said he and his men decided to enter the camp. They were shocked by what they saw.
"We saw emaciated people -- very thin, tired, with blackened skin," he says. "They were dressed in all sorts of different ways -- someone in just a robe, someone else with a coat or a blanket draped over their robe. You could see happiness in their eyes. They understood that their liberation had come, that they were free."
In Pictures: Auschwitz Then And Now (Click here to view)
The unit stayed no more than half an hour, attempting to communicate with prisoners who Martynushkin now believes were Hungarian Jews. "We all spoke a bit of German, English, and Polish by then, but we had no idea what language these people were speaking," he says.
But despite the language difficulties, the prisoners' happiness was infectious, Martynushkin says. "We could feel that we had done something good."
Martynushkin, who is Russian, continues to harbor positive memories of the Soviet Army's role in the liberation of the vast Auschwitz network of camps.
He has attended numerous commemorative events, even receiving an honorary medal from Vladimir Putin at a major ceremony in Krakow marking the 60th anniversary of the liberation in 2005.
But since then, he says, the event has been marred by political sparring.
Putin, whose relations with Poland have dimmed over the ongoing war in Ukraine, will not be attending this year's 70th anniversary ceremonies in Poland.
Moscow is also bristling over a Polish statement that it was Ukrainians who liberated Auschwitz. Speaking on January 21, Russian Foreign Minister Sergei Lavrov said the Soviet Army was multinational by nature and that "Russians, Ukrainians, Chechens, Georgians, Tatars" all participated in the liberation.
Martynushkin says he is happy to live to see the 70th anniversary, but disappointed the historic event has been overtaken by political feuds -- particularly so soon after the display of European solidarity that followed the terrorist attacks earlier this month in Paris.
"I thought that the date associated with the liberation of Auschwitz, these historic events, might deserve the same kind of public unity," he says.
"In spite of all the strife and all the different approaches to things going on in the world, we should have been able to come together and pay proper tribute to those events and those people who died. But unfortunately, that didn't happen."
Daisy Sindelar contributed to this report