The Soviet invasion of Ukraine was a major offensive by the Ukrainian Front of the Red Army against the Ukrainian People's Republic (UPR) during the Soviet–Ukrainian War. The invasion was first planned in November 1918, after the Council of People's Commissars of the Russian Soviet Federative Socialist Republic annulled the Treaty of Brest-Litovsk, and was launched in the first days of January 1919 with the occupation of Kharkiv. Its aim was to join Ukraine to the RSFSR, as the country was of significant economic, demographic and strategic importance for the Bolsheviks. In the longer term, the capture of the Black Sea coast was to prevent an intervention by the Allies in support of the Volunteer Army. Finally, the Bolsheviks intended to extend the area they control as far as possible to the west, in order to be able to support the other revolutionary movements in Europe.

In the first days of January 1919, by joining forces with local workers' units, the troops of the took Kharkiv, which was announced as the seat of the Provisional Workers' and Peasants' Government of Ukraine. Then they quickly captured most of northern and eastern Ukraine, and on 5 February 1919, they occupied Kyiv. The Directorate of Ukraine moved to Vinnytsia, then to Kamianets-Podilskyi. By spring, the Red Army had reached the Zbruch and repelled a counteroffensive by the Ukrainian People's Army (UPA) that threatened Kyiv.

The introduction of the policy of war communism and the requisitioning of food for the needs of the cities quickly alienated a significant part of the Ukrainian peasantry from Bolshevik rule. The outbreak of a number of local uprisings, and in May 1919, the rebellion of the 20,000-strong forces of Nykyfor Hryhoriv, prevented the Red Army from finally destroying the UPA and marching west towards Bessarabia and Hungary. At the end of June, the Red Army suffered a series of defeats in clashes with the Volunteer Army in Donbas, losing Katerynoslav and Poltava by the end of June 1919, as well as those territories captured in the course of operations against Mykolaiv and Odesa. In August, the Red Army also succumbed to the offensive of the combined forces of the Ukrainian People's Army and the Ukrainian Galician Army. On 31 August, Kyiv was captured, first by the Ukrainian People's Army, and then, after their withdrawal from the city, by the Volunteer Army.

Planning On 12 November 1918, at the direct command of the Council of People's Commissars, the Revolutionary Military Council of the Russian SFSR, headed by Leon Trotsky, dismissed Vladimir Antonov-Ovseenko from the Ural Front and ordered him to prepare an offensive in the direction of Ukraine within ten days. The Ukrainian Revolutionary Military Council was immediately established, including Antonov-Ovseenko, Joseph Stalin, Volodymyr Zatonsky and Georgy Pyatakov. Over the next two days, Antonov-Ovseenko developed an offensive plan. It was based on the assumption that, in the first place, the Bolshevik forces should seize cities, industrial centers, ports, and railway junctions, which would provide the necessary resources and guarantee the possibility of gaining support from the workers. In the first move, Antonov-Ovseenko planned to attack Kharkiv, which would then become the base for the march to Donbas. The second step was to capture Kyiv, and the third step was to capture southern Ukraine and the Black Sea coast, including the key centers of Mykolaiv and Odesa.

As the commander-in-chief of the Red Army Jukums Vācietis adopted the Antonov-Ovseenko plan without amendments, he decided that he would receive in the course of operations all the necessary replenishment (including armored trains) and supplies. In particular, the commander of the Ukrainian Front expected that he would have at his disposal the Reserve Army under the command of Vasily Glagolev. Vacietis, however, assigned him completely different tasks - participation in the defense of Voronezh against Pyotr Krasnov's Don Army and Anton Denikin's Volunteer Army. This was in line with Vladimir Lenin's expectations - while Trotsky was convinced that the seizure of Ukraine should be a priority for the Red Army, the chairman of the Council of People's Commissars considered it more important to repel direct threats by the White movement to the Southern and Eastern Fronts. An additional source of conflicts between Vacietis and the Ukrainian Revolutionary-Military Council was the conviction of Stalin, Zatonsky and Pyatakov that they were performing a task of special importance, independent of other operations conducted by the Southern Front.

At the disposal of Antonov-Ovseenko were initially the and , as well as the 9th division, to which new volunteers were constantly arriving, but which needed urgent additions to hardware and supplies. The two Soviet Ukrainian divisions, formed in mid-1918 by the Ukrainian Bolsheviks in order to fight the government of Pavlo Skoropadskyi and the Central Powers, did not have high combat value. Many volunteers who joined them during the formation intended to fight only in their local area and deserted when the fighting moved to other regions.

On 20 November, Antonov-Ovseenko directed orders both to the line units of the Red Army and to irregular units in Ukraine that were participating in the anti-Hetman uprising and recognizing, at least formally, the sovereignty of the . He ordered the revolutionary troops in Homiel to maintain control of the city in order to prevent anti-Bolshevik forces from moving from Kyiv towards Kursk and Bryansk. Those operating in the regions of Katerynoslav and Kharkiv were ordered to initiate local revolts, take control of smaller towns in order to facilitate the Red Army's march south, help in the capture of Kharkiv and, in the longer term, Mykolaiv. Bolshevik supporters in northern Donbas were called on to organize guerrillas and take control of the region, and those who were in Crimea - to prepare to repel possible Allied intervention on the peninsula. In November 1918, a wave of strikes broke out in cities in eastern Ukraine and partisan troops also operated outside the cities. Meanwhile, on 21 November, Vacietis ordered Antonov-Ovseenko to focus on the expansion and training of troops and to set up a strike group that would attack the forces of Pyotr Krasnov at Millerovo. Troops of the Don Cossacks, with the consent of the retreating Germans, took control of the Donbas from them.

The commander of the Ukrainian Front decided to ignore the orders of the high command, offended by the tone and wording contained in the Vacietis directives. Having learned about the landing of the first Allied ships in Odesa, Antonov-Ovseenko decided to lead the offensive according to his own concept. At the same time, Pyatakov and Zatonsky began to form a Bolshevik government for Ukraine. Although in October 1918, the Bolshevik government had concluded an agreement with the Ukrainian socialist leader Volodymyr Vynnychenko, under which it was not to interfere in the internal affairs of the Ukrainian People's Republic, in exchange for consent to the legal operation of the communist party within its borders. However, it was decided to undertake military intervention. On 28 November 1918, the Provisional Workers' and Peasants' Government of Ukraine was established in Kursk.

Invasion

Kharkiv offensive In December 1918, the Ukrainian Soviet divisions were put at the disposal of Antonov-Ovseenko. Numbering approximately 5,000 soldiers each, the divisions were still not full-fledged regular formations. They consisted of undisciplined, largely independent departments. Their commanders included both ideological communists and ordinary peasants. One-third of the red soldiers and guerrillas had no weapons at all. Before the start of military operations, Antonov-Ovseenko relieved the most disgraced commanders from command, but he never gained complete control over the units that made up his front.

Further disputes between Antonov-Ovseenko and Vacietis concerning competences and tactics lasted almost throughout December 1918. Finally, on 2 January 1919, Antonov-Ovseenko made a decision on his own to start the march to Kharkiv, having learned that the last German units were withdrawing from the city and that the Bolshevik workers' units were getting ready to start an armed uprising. On 3 January 1919, the 1st Ukrainian Soviet Division entered Kharkiv. The next day, the Ukrainian Front was formally established with Antonov-Ovseenko as the commander. The Reserve Army was attached to the Front, and Vasily Glagolev was appointed as its chief of staff. A significant part of the partisan peasant units in Ukraine, which had previously fought against the Germans and sympathized with Petliura, defected to the Soviet side, under the influence of Bolshevik agitation. The urban proletariat of non-Ukrainian origin also joined the fight on the side of the Red Army.

March on Poltava, Katerynoslav and Kyiv After the capture of Kharkiv, the offensive of the Ukrainian Front significantly accelerated. On 12 January 1919, the Red Army captured Chernihiv and, on 20 January, it successfully captured Poltava after a sixteen-day battle for the city. Units of the 2nd Ukrainian Soviet Division, led by Pavel Dybenko, entered Katerynoslav, which the Petliurists and Makhnovists had been fighting fiercely over. On 18 January 1919, Antonov-Ovseenko, who moved his quarters from Kursk to Chernihiv, accelerated the preparations for the march to Kyiv. He expected that the Allies who landed in Odesa and Crimea also intended to launch an offensive in the same direction, in support of Anton Denikin's Volunteer Army. However, the negotiations of the Directorate with the French regarding active military aid ended with the French refusing.

In the face of the invasion, treating the Red Army's march as an expression of Russian imperialism, Vynnychenko's Ukrainian socialists supported the defense of the country's independence. However, it turned out to be impossible to successfully repel the march of the Ukrainian Front, as the forces loyal to the Directorate were dwindling with each passing day. The Ukrainian national movement did not have a broad social base, being the domain of mainly a narrow intelligentsia. In addition, the Directorate was weakened by internal disputes between nationalists and socialists. At the end of January, only 21,000 soldiers remained loyal to the Ukrainian government. On 23 January, Symon Petliura began the evacuation of military personnel from the capital to avoid a battle, the outcome of which would be a foregone conclusion.

Meanwhile, the Bolshevik troops continued to grow, after the occupation of Kharkiv, as the 1st Ukrainian Soviet Division alone reached over 10,000 soldiers. The Ukrainian capital was left without a fight, seized by the 1st Ukrainian Soviet Division on 5 February. Earlier, on 29 January 1919, the Provisional Workers' and Peasants Government was transformed into the Council of People's Commissars, headed by Christian Rakovsky. The directorate moved to Vinnytsia, and then to Kamianets-Podilskyi.

By the end of January, the Red Army had captured the entirety of left-bank Ukraine. In early February, partisan units allied with the Red Army seized Znamianka, Kryvyi Rih and . A workers' uprising broke out in Yelysavethrad, the participants of which, after joining forces with the partisans, seized the city. On 12 February, Novomyrhorod was seized. The Red Army continued their march south and west into areas controlled by Allied interventionist troops. By this time, there were 200,000 people in the Red Army, as the anarchist forces of Nestor Makhno were incorporated into the Ukrainian Soviet ranks and the peasant division of otaman Nykyfor Hryhoriv also defected from the side of the Ukrainian nationalists to the Soviets.