
An often-overlooked theatre of the Russian front during the Second World  War is the vicious and brutal campaign waged by partisans behind the  German lines. By the time the Red Army began its victorious drive west  to the frontiers of the Third Reich in 1944, there were over  half-a-million partisans operating deep within German-held territory.  The partisans, men and women living in the woods and marshes of Belarus,  Ukraine, the Baltic States and Western Russia, played a significant  part in disrupting German supply, communications and transport to the  front lines, and forced the SS and Wermacht to keep large formations of  troops away from the front to secure their vulnerable logistical  systems.
In the end it was, as in all wars, the civilian  population that would suffer the most in the fighting between nazi  German forces and the partisans. German reprisals consisted of killing  10 civilians from the nearest villages for every one German soldier  killed by partisans, while the partisans themselves would raid their  countrymen's villages for food and supplies and to root out and kill  anyone suspected of collaborating with the Germans.
At the  beginning of Operation Barbarossa, the surprise German invasion of the  Soviet Union in June 1941, explicit orders had been given to the German  armed forces concerning resistance in the rear areas. Titled "Guidelines  for the Conduct of Troops in Russia", this order read "Bolshevism is  the mortal enemy of the National Socialist German people. This battle  demands ruthless and energetic measures against Bolshevik agitators,  irregulars, saboteurs and Jews and the total eradication of any active  or passive resistance." Many German officers, tried after the war for  war crimes and crimes against humanity, would fall back on these  'guidelines' as proof that they were simply following orders. In any  case, this order certainly gave the average German soldier a license to  greatly mistreat the civilian population in occupied areas of the Soviet  Union.
As German forces drove through the Baltic states and the  Ukraine, the people at first welcomed them as liberators from Stalin and  his ruthless secret police, the NKVD. Ukrainian girls kissed smiling  German soldiers as they marched through captured villages, and in the  Baltics flowers were thrown on tanks by the grateful population. The  same scenes were repeated in western Belarus but, within a short time,  it became apparent that no matter how totalitarian Stalin's rule had  been, life under the nazis was infinitely worse.
The ruthless 
Einzatsgruppen of the SS were tasked  with destroying the Jewish population of the Soviet Union but their  mission quickly came to include terrorizing the non-Jewish civilian  population. Members of the SS were generally fanatical Nazis, and as the  elite praetorian guard of Hitler and the Nazi party, membership to the  SS was only granted to the most devoted of National Socialists. As a  result SS members believed in the theory of racial superiority and the  threat that Jews, Slavs and other "subhumans" posed to the "pure"  Germanic-Aryan race. The people of the Ukraine and the Baltics who had  at first greeted the Germans with flowers were soon turning to acts of  terrorism as SS atrocities against them increased.
SS Einzatsgruppen execute Jewish civilians in Belarus
The first partisans were disorganized and badly equipped. In the summer  of 1941 the Germans had surrounded large pockets of Red Army troops at  Minsk, in Belarus, and Smolensk in Western Russia. Most of these hapless  soldiers surrendered to the Germans but many of them melted away into  the dense forests of the area. In smaller battles across the front, and  in areas by-passed by the German advance, Red Army units did the same.  The 
Wermacht never had the  resources to effectively police and control the vast territory of  conquered Russia. The bulk of its fighting manpower was needed at the  front, so the task of taming the rear areas fell to the SS.
These  small groups of Red Army "leftovers" started ambushing German army  transports heading to the front in order to steal food, clothing and  weapons. The men were living in forests and hiding from the roving  patrols of the SS. In some areas, like the Pripet Marshes in north-west  Russia, Red Army units linked up to form partisan bands over 2,000  strong! Most of the bands, however, were no bigger than ten or twenty  men surviving by raiding and stealing.
After the German defeat at  the gates of Moscow and as the terror of the German occupation  increased, more and more of the civilian population were disappearing  into the forests, sometimes to join up with Red Army groups and many  times to form their own partisan bands. In the Ukraine many of the  civilian partisan bands fought with both the Germans and other Red Army  groups, and they continued to fight the Red Army for years after the war  had ended.
A young partisan woman milking a cow for her camp.
Partisans on the move in a Russian forest. Note the captured German uniforms and equipment.
The civilian groups were made up of both men and women, old and young.  They were incredibly effective in wrecking German transport and supply  lines and constituted a greater threat, at least at the beginning of the  war, to German logistics than the Red Army partisans. Railways were  mined and locomotives blown up. Groups of civilians, using captured  German machine guns and rifles, would leap out of the forest and shoot  up German trucks or cars unlucky enough to be travelling on their own.  Small groups of German soldiers on leave behind the lines would be  kidnapped and killed and left on display for other Germans to see. Fuel  and ammunition dumps would be attacked and destroyed and their garrisons  killed. Military airfields, with their larger garrisons, were not safe  as partisans would storm the fences at night and blow up as many  warplanes as possible before melting away into the surrounding forests  again.
These partisans built up huge camps within the forests.  Bunkers were dug and buildings erected out of felled trees. In some  camps there were makeshift hospitals, mess halls and even nursuries for  newborn children of partisan women.
Russian female partisans fought alongside their male counterparts. After the war the Soviet Union registered over 30,000 marriages between men and women who fought together as partisans.
The partisans also conducted  raids on their own countrymen who collaborated with the Germans.  Civilian police stations in the occupied territories were frequent  targets, and assasinations of mayors, businessmen and other people who  sought to profit off the German occupation were frequent. Villages which  refused to supply local partisan groups with food were sometimes  destroyed, although this was more common near Red Army partisan units  than with civilian partisans.
The arch-enemy of the partisans  remained the SS. As the war on the eastern front progressed the  partisans were emboldened by Soviet victories at places such as Moscow,  Stalingrad and Kursk and by the relatively few German forces available  to subdue the rear areas. Supply to the German front was becoming  catastrophically disrupted due to partisan activity, so much so that  Berlin ordered the creation of special SS combat groups to hunt down and  destroy partisan units hiding out in the forests.
Supplied with  aircraft, tanks, armored vehicles and light artillery, these SS groups  were able to quickly move from one area to another whenever intelligence  revealed the location of a partisan group. 
Gestapo investigators were attached to each combat  group. Increased partisan activity in an area could reveal an  approximate location of a unit, but diabolical schemes could also root  them out of their forest hideouts. For example, it became a common, and  effective, tactic to capture a couple of partisans and, after extensive  torture, discover which local villages they enjoyed support from. The SS  would then move in to those villages and round up the inhabitants and  shoot or hang or, in some cases, crucify them all and then burn the  village to the ground.
These acts would cause the local partisans  to come out of hiding, whether to investigate the atrocity, to find new  sources of supply or simply to seek revenge for the deaths of their  families and destruction of their homes. The SS would be lying in wait  and would ambush the partisans, and then chase the survivors back into  the woods to overrun their camps.
These SS units became  specialist partisan fighters. Recconaissance aircraft would also be used  to locate partisan camps at which point the SS would storm the forest.  Some incredibly vicious battles ensued behind the lines, with partisan  units defending their camps and SS stormtroopers attacking the  perimeters to crush them.
An SS firing squad executing partisans in the Ukraine.
A Russian family left homeless after the SS swept through their village.In 1942, after the battle of Stalingrad, the 
stavka, the Soviet military high command, took an  interest in the strategic value of the partisans and began to parachute  radio sets, weapons and experts in guerilla warfare to the partisans.  The Red Army groups were organized into cohesive fighting units and  massive operations behind the lines were conducted. As a result, in the  lead-up to the decisive battle at Kursk, nearly 1/4 of all German  supplies earmarked for the offensive never reached their frontline  units. For example, in northern Ukraine an army train transport carrying  new Panther and Tiger tanks, along with all their fuel, ammunition and  crews, was ambushed by partisans. 36 of the valuable tanks were  destroyed on the train flatbeds and over 100 of their crews were killed.  Most of the fuel and ammunition was set on fire.
More and more  German soldiers were forced to patrol and garrison behind the lines,  thus keeping out of the battles at the front. Historical estimates put  the number of frontline-worthy German troops, from both the 
Wermacht and the SS, that were  stationed behind the lines because of partisan activity, at over  100,000, or enough to supply another whole German army.
Following  the battle of Kursk the Red Army began its drive west, recapturing  Soviet territory and eventually overrunning all of Eastern Europe and  half of Germany. In this final phase of the war, partisan activity  escalated beyond all means of the Germans to control it. As Soviet  forces neared, partisans became more bold, attacking strong German  garrisons and even the vaunted SS special combat groups. Retreating  German soldiers, hoping to escape from the avenging Red Army that was  nipping at their heals, found nowhere safe to escape. As German soldiers  marched back the way they had come three years earlier, they found only  the corpses of their comrades who had gone before them until they in  turn were attacked by formations of furious partisans. Morale in the  German army crumbled, and the constant attacks by partisans caused  massed confusion among the retreating formations, making it impossible  for commanders to assemble their units into defensive lines.

Carnage on the German rail lines, courtesy of the partisans.
Partisans investigate a Luftwaffe airfield they have just destroyed.By 1944 partisan units controlled vast areas of territory, and instituted their own governments and enforced their own laws. As the Red Army swept through these areas, the partisans were rounded up and drafted into regular army units. Many resented this but dissenters, in typical Stalinist fashion, were executed or sent to Siberia by their own government in spite of the sacrifices they had made for the cause.
Stalin was so paranoid of the independence of these partisan units that after the war a mass roundup of all those who had fought in a civilian partisan unit was conducted. Over 100,000 former partisans were sent to the 
Gulag and it wasn't until after Stalin's death in 1955 that they were granted amnesty and allowed to return home.
The total number of partisans killed or Germans killed by partisans is impossible to calculate. There was no registration system in place for partisans, and the number of people who claimed to have fought with the partisans after the war must be suspect (Stalin had decreed that every Soviet citizen had a sacred duty to either fight or die and those people caught up in the German occupation were later punished by Soviet authorities, so many resorted to claiming that they were partisans). What is known is that many, if not most, of the partisans killed in the war lie in unmarked graves.
In 1960 it was decided that military medals should be awarded to veterans of the partisan war, and in 1995, to celebrate the 50th anniversary of the victory over Nazi Germany, special commemorative coins were minted celebrating the contributions that every man and woman who fought against Nazi tyranny made.