Zinoviev soon returned to the fold and was once again elected to the Central Committee at the VII Party Congress on March 8, 1918.
He was put in charge of the Petrograd (Saint Petersburg before 1914, Leningrad 1924–91) city and regional government.

Sometime in 1918, while Ukraine was under German occupation, the rabbis of Odessa ceremonially anathematized (pronounced herem against) Trotsky, Zinoviev, and other  Bolshevik leaders of Jewish descent in the synagogue.


Shortly after the assassination of Petrograd Cheka leader Moisei Uritsky in August 1918 and the commencement of the five year Red Terror period of political repression and mass killings, Zinoviev said: 
To overcome our enemies we must have our own socialist militarism.
We must carry along with us 90 million out of the 100 million of Soviet Russia's population.
As for the rest, we have nothing to say to them.
They must be annihilated.

He became a non-voting member of the ruling Politburo when it was created after the VIII Congress on 25 March 1919.
He also became the Chairman of the Executive Committee of the Comintern when it was created in March 1919.
It was in this capacity he presided over the Congress of the Peoples of the East in Baku in September 1920 and gave his famous four-hour speech in German at the Halle congress of the Independent Social Democratic Party of Germany in October 1920.

Zinoviev was responsible for Petrograd's defence during two periods of intense clashes with White forces in 1919.
Trotsky, who was in overall charge of the Red Army during the Russian Civil War, thought little of Zinoviev's leadership, which aggravated their strained relationship.
Zinoviev soon returned to the fold and was once again elected to the Central Committee at the VII Party Congress on March 8, 1918. He was put in charge of the Petrograd (Saint Petersburg before 1914, Leningrad 1924–91) city and regional government.
Sometime in 1918, while Ukraine was under German occupation, the rabbis of Odessa ceremonially anathematized (pronounced herem against) Trotsky, Zinoviev, and other  Bolshevik leaders of Jewish descent in the synagogue.

Shortly after the assassination of Petrograd Cheka leader Moisei Uritsky in August 1918 and the commencement of the five year Red Terror period of political repression and mass killings, Zinoviev said: 
To overcome our enemies we must have our own socialist militarism. We must carry along with us 90 million out of the 100 million of Soviet Russia's population. As for the rest, we have nothing to say to them. They must be annihilated. 
He became a non-voting member of the ruling Politburo when it was created after the VIII Congress on 25 March 1919. He also became the Chairman of the Executive Committee of the Comintern when it was created in March 1919. It was in this capacity he presided over the Congress of the Peoples of the East in Baku in September 1920 and gave his famous four-hour speech in German at the Halle congress of the Independent Social Democratic Party of Germany in October 1920.
Zinoviev was responsible for Petrograd's defence during two periods of intense clashes with White forces in 1919. Trotsky, who was in overall charge of the Red Army during the Russian Civil War, thought little of Zinoviev's leadership, which aggravated their strained relationship.
Grigory Zinoviev