A short time after the German invasion of the Soviet Union, the Central Committee of the Communist Party ordered its members to organize an armed Underground in the occupied territories, which would act against the German Forces operating in those areas.
Plans for projects such as this have been prepared even before the war.
Although the order was issued in 1941, conditions for an Underground began to appear only in 1942-43.
These conditions were identified principally in Ukraine, Belarus and western Russia.
The Partisans started to conduct Guerrilla warfare against the invaders, while winning mounting support and sympathy from the local population that was already suffering from the German cruelty.
The Partisans were comprised of “Red Army” Soldiers and Officers who had stayed behind in the territories that had been swiftly occupied by the Germans in the early stages of their Offensive, refugees who had fled other areas and joined Underground activities, and also local residents.
There were no orderly enlistment procedures to the Partisans.
Jews operated in Partisan Units throughout the occupied territories, including the Ghettos. They joined Soviet Partisan Groups and also formed Groups of their own that operated in the framework of the Soviet ones. Jewish Fighters were generally composed of young people who had run away from Ghettos or from other places where they had been living, and of Soldiers who were serving in the Army but stayed behind in territories occupied by the Germans. There were also Jews from other Countries, such as Hungary, among the Partisans; they had come to the occupied territories as forced laborers and then escaped and joined the fight against the Germans.

Most of the Soviet Partisan Forces were concentrated in Belarus, and numbered over 300,000 Fighters. Starting in the spring of 1942, these Forces caused the German Forces significant troubles and affected their operations in the area. The Partisan activity aimed primarily at disrupting the train system, gathering Intelligence and attacking the rear of the German Army. The number of German casualties, including those wounded and captured, was estimated at about 1.5 million Soldiers.
In the latter part of the war, the Partisans’ main operations were conducted in coordination with Soviet Offensives. The Soviet Army supported Partisan Forces considerably by transporting equipment and supplies to them through the air. Partisans who were operating in territories liberated by Soviet Forces joined the “Red Army” and continued to fight the enemy within that framework. 
Jewish Underground activity in Belarus was most noticeable at the Minsk Ghetto and in the forests around the City.

Partisan Units were also organized in Ukraine but did not become a significant force until 1943, when their members numbered approximately 150,000 persons. In the vicinity of Bryansk, the Partisans controlled vast areas in the rear of the German Forces. By the summer of 1942, about 60,000 Partisans had control of 14,000 square-kilometers where a population of over 200,000 people was living. Partisan operations had a significant impact on the Germans in other occupied areas as well, such as Belgorod, Kursk, Novgorod, Pskov and Smolensk. Jews were active in all Partisan Units in Ukraine, in the forests and in the towns.

In the Baltic States, Partisan Forces operated under a central direction from Moscow and were primarily engaged in attacks on the train system. Most evident were the activities of the Underground Organization at Kovno and Vilna Ghettos, which had been established by Communist activists and Zionist Jews under the leadership of Yitzhak Wittenberg and writer Abba Kovner. (See “The Fighters” section.)

Partisans in U.S.S.R. territories caused the Axis Armies hundreds of thousands of casualties and contributed greatly to the Soviet victory over its German-Nazi enemy.

The total number of Jews in the various Partisan Groups is estimated at approximately 50,000 men and women. Many of them reached command positions in their respective Units.

Many Operatives in the Soviet Partisan Movement’s Intelligence Array during World War II were of Jewish descent. Their activities in the German occupied territories, under constant life-threatening conditions, yielded a degree of fruit that certainly contributed to the Soviet Union’s overall Intelligence effort. The most famous of these Jewish Partisans was Hero of the Soviet Union, Dmitry Medvedev.

The Soviet Partisan Intelligence Array’s inception dates back to the early months of the German Army’s invasion of the U.S.S.R. Despite the initial shock from the military defeat, numerous Partisan Groups started to form spontaneously in the rear of the occupier.
Elements of the Communist Party, the Commissariat for Internal Affairs (NKVD) and Military Intelligence (GRU) managed to take control over most of these Groups and establish a wide operational infrastructure on their basis, upon which a Soviet Partisan Movement was already emerging by late 1941.
In May, 1942, the Movement’s Central Headquarters was established in Moscow, with operation controlling Branches in the occupied Soviet Republics (Ukraine and Belarus Staffs, and others). The Central Headquarters, as well as its subordinate Staffs, included large Intelligence Departments that, collectively, constituted what was called the Intelligence Array of the Soviet Partisan Movement.
Partisans of Jewish descent started gathering Intelligence even prior to the formation of the Soviet Partisan Movement Central Headquarters. In late 1941, after the German Offensive was halted near Moscow, Soviet Intelligence began to find a growing operative interest in Partisan infrastructure that had already existed in the occupied territories, and thus, Jews taken into its ranks were assigned to a rather varied Intelligence activity.
Conspicuous among Partisan Commanders of Jewish origin who were already active behind Front lines in the early months of the German occupation was Isay Kazinets, of the Underground Group that operated in Minsk, Capital of Belarus.
Kazinets and his men’s most significant achievement was acquiring a complete sketch of German Institutions, both civilian and military, that had been spread throughout the City of Minsk after its occupation.
The Operation, in which this sketch was obtained, was carried out by a worker in the German Administration, semi-Jewish, who had been recruited by Partisan Intelligence. According to Russian sources, Isay Kazinets’s Underground was exposed and eliminated by German preventive Intelligence, in March, 1942.
Kazinets himself and some of his men were severely tortured and then hanged in central Minsk, on 7 May 1942.

Parallel to the activity of the Partisans, whose Groups formed spontaneously in German occupied territory, were the Intelligence Services of the Soviet Union, already working in the second half of 1941 to put in place an organized Partisan infrastructure under a central Partisan command.
Two Jews in this Command stood out – Nahum Eitingon and Yakov Serebryansky – veterans of the Soviet Foreign Intelligence Service, who participated in large NKVD Intelligence Operations in the 1930’s. Eitingon was assigned the management of sabotage and intelligence activity behind the Front line, whereas Serebryansky was put in charge of the “Special Group” within the Organization that trained sabotage and intelligence squads and facilitated their infiltration of the occupied territories.
Among the numerous Intelligence squads that penetrated across the Front, there were teams in which both the Commanders and the Fighters were of Jewish descent.
A fundamental shift in activity occurred in mid-1942, following the establishment of the Partisan Movement’s Central Headquarters in Moscow along with its Intelligence Array. Intelligence Departments began to operate throughout the entire structure of Partisan Command – from the Central Headquarters level all the way down to individual Groups in the field.
A large number of Jews served as Staff Officers and Agents in the new structure; many of them had previous experience in intelligence work.
The most senior among them was Lieutenant-General Rafail Khmelnitsky, the first Commander of the Intelligence Department in the Partisan Movement’s Moscow Headquarters.

Notable Jewish Intelligence Operatives in the field were people like Mikhail Imas Kats, a native of Kishinev, Moldova, famous for daring intelligence operations he performed among enemy Officers while disguised as a German Major; and also, I. Drakhler, for reporting the exact location of Hitler’s Field Headquarters in the Region of Vinnitsa, Ukraine.

The most famous of Jewish Partisans was Dmitry Medvedev, Hero of the Soviet Union, who reported about the Germans’ intention to assassinate world leaders Churchill, Stalin and Roosevelt in the course of the Tehran Conference, in 1943.