The main task of the Anti-Terrorist Operation Forces was to restore control over the section of the state border Izvaryne – Kumachovo[18] and to cut the routes for illegal armed groups.

Establishing border control was a key point in the peace plan of newly elected President Petro Poroshenko.

Another high-profile incident occurred on 13 May, when the wounded self-proclaimed Luhansk "governor" Valery Bolotov was able to leave Ukraine through the Dovzhansky checkpoint.

[20] On 17 May, border guards detained Valery Bolotov at the Dovzhansky checkpoint at 5:45 am, informed all law enforcement agencies, including representatives of the anti-terrorist operation, and waited for about two hours for help from security forces, but no one arrived.

On 30 May, border guards in the direction of Novaya Nadezhda (Russia) – Dibrivka (Ukraine) detained armed individuals with a significant number of weapons while attempting to enter illegally.

[27] Personnel, weapons, ammunition, and equipment from the Stanychno-Luhanske, Krasnodon, Biryukovo, Sverdlovsk, and Dyakovo Luhansk Oblast Border Service were redeployed.

A convoy of militants, consisting of an armoured personnel carrier, four Kamaz trucks, three minibuses, and four cars invading from Russia, attacked the border checkpoint.

On 12 June, tanks were transferred to Ukraine from the Russian Federation,[36] crossing the border at night, passing through Snizhne, Torez, and Makiivka, and entering Donetsk.

[37] In the evening of 12 June, Poroshenko held a meeting with the heads of law enforcement agencies on the invasion of tanks of the Russian Federation.

Border control and the creation of a 10 km buffer zone was one of the key points of the peace plan proposed by newly elected President Petro Poroshenko.

Later, Secretary of the National Security and Defense Council Andriy Parubiy said that the state border was closed in accordance with the task set by the President.

[40] The initial task of the anti-terrorist operation group was to isolate the anti-terrorist operation area, regain control of the 140-kilometer section of Ukraine's state border with the Russian Federation on the Izvaryne-Kumachyovo section to prevent the groups of Russian mercenaries from crossing the border and eliminate militant and separatist lines, weapons and ammunition.

Border control was to make it impossible for the militants to use the five main routes through which the militant-controlled territories were connected with the Russian Federation, specifically the Uspenka, Marynivka, Dovzhansky, Chervonopartizansk and Izvaryne.

Plans included creating fortified defense points, which could destroy the enemy moving through highways and steppe areas with artillery fire.

[41] The operation was scheduled to begin on 17 May, but had to be postponed due to an attack on a 51st mechanized brigade checkpoint near Volnovakha, as a result of which the demoralized unit was temporarily withdrawn to the rear.

On 5 June, militants from Donetsk and Shakhtarsk arrived in Amvrosiivka, numbering several hundred people with several armored personnel carriers and about ten trucks.

During 8 June, the militants continued fortification work in Snizhne: set up checkpoints, dug trenches, and equipped firing points.

16 June, the Secretary of the National Security and Defense Council at a briefing said that in the Donetsk and Lugansk regions of the ATO forces to resist 15 000 – 20 000 militants.

[51] Lugansk militants were more than 4,000 people armed with light rifle weapons and integrated into several groups, including: From 9 July to 5 September 2014, the State Border Service of Ukraine and the National Security and Defense Council reported more than 120 attacks of Russian artillery.

[53] In the morning of 11 July 2014, as a result of unexpected massive artillery attacks on military targets in the area of Zelenopoly, 30 were killed and more than 100 soldiers were injured.

By the end of July 2014, the massive artillery fire led to significant losses and contributed to the consequent withdrawal of the Ukrainian forces.