Sergei Nikiforovich Kruglov (2 October 1907 – 6 July 1977) was the Minister of Internal Affairs of the Soviet Union from January 1946 to March 1953 and again from June 1953 until February 1956.

[1] Sergei Kruglov was born on October 2, 1907, in a village in the Tver Governorate of the Russian Empire; his family was of poor peasant stock.

During the initial months of the war he organized special Blocking Detachments, which performed mass executions of Soviet military personnel accused of desertion or unauthorized retreat.

For his role in organizing these deportations, Kruglov was awarded the Order of Suvorov, first degree, which was usually given for exceptional bravery in front-line combat.

[1][8] On January 1, 1946, Kruglov replaced Lavrentiy Beria as the People's Commissar of Internal Affairs of the Soviet Union (head of NKVD).

NKGB became the Soviet Ministry of State Security (MGB), and it was headed by Viktor Abakumov, who replaced Beria's protégé Vsevolod Merkulov.

The elevation of Kruglov and Abakumov is now seen by historians as part of a deliberate strategy by Joseph Stalin to limit Beria's influence after the end of the war.

In 1948 Kruglov organized mass deportation of the German population of the Kaliningrad oblast (formerly East Prussia) – the area around Königsberg that was annexed by the Soviet Union at the conclusion of World War II.

In January 1948 Kruglov and Abakumov presented for Stalin's signature a memorandum that significantly toughened the Gulag conditions for political prisoners.

MVD was authorized to hold, when deemed necessary, such political prisoners beyond the expiration dates of their sentences and to send them to the so-called administrative exile (административная ссылка) in the cases where formal release did occur.

Beria and Malenkov engineered the so-called Leningrad Affair which resulted in the persecution of many party officials connected to Zhdanov.

In March 1953 MGB was merged into MVD and Beria became the Minister of Internal Affairs with Sergei Kruglov serving as his First Deputy.

[11] Both Kruglov and Ivan Serov played key roles[11] in the June 1953 arrest of Beria, engineered by Nikita Khrushchev and Malenkov.

[14] Kruglov remained the Minister of Internal Affairs until 1956, although in 1954 MGB was again split away from MVD and renamed as KGB, with Ivan Serov becoming its head.