The Crimean peninsula is connected to mainland Ukraine by the Perekop Isthmus that is only 8 km wide. To get to Crimea, one can go by road, rail, air or by sea.

Three main highways connect the peninsula with mainland Ukraine. The routes on the Perekop Isthmus run through Kalanchak and Chaplynka (Kherson Oblast). There is yet another one that goes across the bridge connecting Crimea with the Chongar Peninsula. And there are also other, less popular and convenient roads, which had been of little significance transit-wise even before the events of 2014.

Passenger rail link had two branches: across the Perekop Isthmus and the Chongar Peninsula. Civil aircraft would land in Crimea at the airports of Simferopol and, less frequently, Sevastopol (Belbek). Passenger shipping at the seaports of Crimea (Yalta, Sevastopol) was primarily of recreational rather than transit importance.

Russia is separated from Crimea by the Kerch Strait. Before the construction of the road and rail parts of the Crimean Bridge in 2018-2019, traffic by these modes of transportation would go by ferry between the ports of Kavkaz (Russia) and Krym (Ukraine).

To control the passenger traffic through regular channel (planes, ships, trains, buses), one would need to take control of the airports, seaports, railway and bus stations in Crimea. Personal cars and official road vehicles are something else entirely. These needed to be intercepted on the main routes connecting Crimea with Kherson Oblast.

According to the former commander of the Sevastopol Berkut unit, then the head of the so-called "Russian Guard Directorate for Sevastopol", and now - Senator of the Russian Council of Federation from the so-called "Legislative Assembly of Sevastopol" Colonel Sergei Kolbin, the involvement of Berkut veterans allowed to strengthen the personnel of checkpoints from 60 to 90-100 men in a matter of days early on.

Andrey Slobodenyuk, a veteran of the special police unit Titan who joined the illegal checkpoints, claims that a week later they were also joined by Russian Cossacks – members of paramilitary groups controlled and funded by the Russian authorities.

Subsequently, representatives of the Cossack groups arrived from Russia at the checkpoints. They came to Crimea by ferry, crossing the state border in the Kerch Strait area. On Perekop and Turetskyi Traverse (the Chaplynka-Armyansk and Kalanchak-Armyansk routes), there were Cossacks of the Taman department of the Kuban Cossack Host, and on Chongar - of the Yekaterinodar department. This is evidenced by a member of the Taman Cossack department Boris Dzhereliyevsky, who participated in the occupation of Crimea.

According to Nikolai Dyakonov, the field ataman of the Union of Cossack Warriors of Russia and the Diaspora of the Don Cossack Host, the participation of the Cossacks in the occupation of Crimea and, in particular, in the activities of illegal checkpoints at the entrance to Crimea, was coordinated at the headquarters of the Black Sea Fleet of the Russian Federation in Sevastopol.

After the Cossacks, units of the Black Sea Fleet marines moved to the checkpoints. They handed over mortars and armored personnel carriers to the Cossacks and withdrew themselves. Boris Dzhereliyevsky mentioned it, referring to the words of the chieftain of the Taman department of the Kuban Cossack Host Ivan Bezugly. Cossacks, comprising of the former military personnel of the Russian Armed Forces formed mortar squads and crews to man the armored personnel carriers at the checkpoints.

Former Ukrainian police officers and Russian Cossacks at the illegally established checkpoints mainly focused on controlling human traffic across the administrative border and searching the vehicles entering or leaving the territory of the Autonomous Republic of Crimea.

They stopped the cars, checked documents and inspected the luggage. Ukrainian citizens and foreigners were arbitrarily detained. The media reported numerous cases of abduction and torture at the illegal checkpoints.

The most notorious case would be the seizure of journalists and Automaidan activists Kateryna Butko, Alexandra Ryazantseva, Olena Maksymenko, photographer Oles Kromplyas, and engineer Yevhen Rakhno on 03/09/2014. According to Ryazantseva, they were beaten, intimidated, threatened with murder, laid face down on the ground and shot at, with the promise to cut off parts of their bodies. The total number of victims of the actions of the former Berkut policemen and Cossacks at the entrance to Crimea has not yet been established.

The paramilitary formations left the checkpoints on 03/20/2014, only to be replaced by the occupation forces of the Border Guard Service of the FSB of the Russian Federation.