The article analyzes previous research and highlights the features of the counterterrorism security of the state as a component of the national security system.
 The article aims at identifying problems with ensuring counterterrorism security during the Russian Federation's war against Ukraine, analyzing Ukrainian legislation in this area, and outlining the ways of forming the counterterrorism security system of the state in the current context.
 The biggest terrorist threat to Ukraine is the large-scale armed aggression by the Russian Federation and the hybrid war, which aims not only to occupy certain territories of Ukraine but also to completely eliminate Ukrainian statehood. This war widely employs terrorist methods including the intimidation and killing of civilians, the use of powerful weapons against populated areas, and the destruction of critical civilian infrastructure.
 The problems above call for a comprehensive reconsideration of the counterterrorism security of the state, given the need to significantly enhance the protection of possible sites of terrorist attacks and to fulfill the tasks of implementing the national security priorities under the 2020 National Security Strategy of Ukraine Human Security Equals the Country’s Security.
 The perpetration of terrorist acts by the Russian Federation against the national critical infrastructure has become a striking challenge for Ukraine, the consequences of which are difficult to overestimate. During the armed aggression, the Ukrainian state has been confronted with new types of terrorist activities, in particular, psychological and nuclear terrorism. All this requires strengthening the counterterrorism capacities for protecting critical infrastructure and other targets of terrorist attacks, primarily through practical and research-based approaches to the counterterrorism security of the state.
 Based on the results of the study, the authors conclude that there is a need to significantly enhance the institutional strengthening of the national counterterrorism system and to revise Ukrainian legislation in this area. The article outlines interrelations between counterterrorism security and other components within the national security system of Ukraine, including security of the state, military security and defense, public security, cybersecurity, nuclear and radiation security, etc. The authors propose to establish an effective system of counterterrorism security of the state, primarily with respect to improving its legislative basis, which calls for the development of the Counterterrorism Strategy in Ukraine that would become the foundation of state policy in countering terrorism.