Public relations, a field of information and communication sciences, has expanded into numerous categories in a short time and on a path of strengthening its academic position. One of them is crisis communication. Crisis communication represents a strategic approach to the phenomenon of crisis, the disruption of regular procedures in the organization, which implies the creation of communication solutions that will be effective in prevention, but also in remediation of a potential problem that represents a threat to the reputation of the actor implementing the public relations program. On the one hand, a crisis situation is a threat, while on the other, it is also an opportunity. If in the times of a crisis control, openness, clarity, credibility, and security are demonstrated, it is possible to emerge from the problem even stronger than before, and achieve a greater degree of respect, which ultimately contributes to strengthening the image. This PhD thesis thematizes crisis communication viewed from the perspective of political communication. The case analyzed is a public health crisis situation caused by the first wave of the spread of the COVID-19 pandemic, which the Government of the Republic of Croatia faced in 2020. The goals of the research were to determine the characteristics of media reporting on the crisis caused by the COVID-19 pandemic, reactive strategies of crisis communication and associated discourses and used media frames, as well as the functioning of the concept of presidentialization in the context of crisis communication. The concept of presidentialization refers to a wide-ranging increase of the influence of political leaders, which takes place because of various factors, for example the internationalization of politics and the weakening of its influence, that is, the ties that once existed between the electorate and political parties. In the conducted research, the focus is on the media dimension of the concept of presidentialization, that is, the visibility of the political leader, the Prime Minister of the Republic of Croatia, in the circumstances of a crisis situation. A strategic approach to communication generally implies a distinction between proactive and reactive models. The same dichotomy is applicable to the field of crisis communication. In a crisis situation, it is crucial to establish control. In this way, false information that can lead to an increase in the scope and complexity of the crisis is suppressed. If possible, it is recommended to act proactively. On the other hand, reactive strategies imply a kind of forced action with the aim of dealing with influences that are external. It was the crisis triggered by the COVID-19 pandemic that influenced the activation of the reactive communication patterns by the Government of the Republic of Croatia. Framing theory originates from sociology and studies the functioning and consequences of frames that exist in social situations, and fit meaning into specific schemes. According to Semetko and Valkenburg (2000), there are five types of media frames. These are: responsibility, economic consequences, conflict, morality, and human interest. The consequences of media framing, whether it originates from the mass media, or the media used by specific organizations, can be far-reaching, and especially in the field of political communication result with shaping and strengthening of political preferences or degree of support for a certain policy, and understanding of a problem that is of public interest. Framing theory is extremely relevant to the field of public relations, where goals are set at three levels: awareness, attitude, and behavior. The concept of discourse unites values, socio-cultural heritage, and ideology. It is particularly important in the context of political relations, which are inherently of such a nature that they involve issues related to power. The research included the official website of the Government of the Republic of Croatia, as well as four news sites - Vecernji.hr, Tportal.hr, Index.hr, and Dnevno.hr. Content analysis and critical discourse analysis methods were used in the research. Using content analysis, presidential tendencies in the Government of Croatia online communication regarding the COVID-19 pandemic were examined, as well as the usage of specific media frames. The same method was used for examining the used reactive communication strategies from the Government, as well as the frames which the news sites used to approach the subject. The theoretical basis in the segment of framing was elaborated through the taxonomy of Semetko and Valkenburg (2000), which lists five types of media frames, while Smith’s (2005) typology was used to examine reactive crisis communication strategies, which consists of seven types of strategies: pre-emptive actions, defensive response, offensive response, diversionary response, vocal commiseration, rectifying behavior, and deliberate inaction. For the purposes of the research, the author created a separate matrix related to reactive crisis communication strategies, while a measuring instrument based on the work of Semetko and Valkenburg (2000) was used to examine media frames. In addition, the intensity of Government of Croatia online communication regarding COVID-19 pandemic in acute phase was examined, and also the correlation between the manifested agendas of the Government of the Republic of Croatia and news sites. Critical discourse analysis was used in order to examine the most important determinants of Government of Croatia discourse in confronting the pandemic. The discourse-cognition-society triangle model of Teun van Dijk (1993) was applied to the units of analysis, the operationalization of which consists of the grouping of “local meanings”, which refer to observable characteristics of the used language, as well as “global meanings”, in which titles and abstracts are important in defining the desired messages. In the critical discourse analysis, the non-linguistic function of language was also observed, through performative expressions that simultaneously perform a certain action. The research included one basic and four additional hypotheses. Basic hypothesis: The existence of a strong positive correlation between the intensity of the threat and the communication of the Government of the Republic of Croatia, which manifests itself through presidentialization in the Internet media. Additional hypotheses: In the releases of the Government of the Republic of Croatia on the official website, during an acute public health crisis, the media frame of responsibility prevails. -- In the reporting of Croatian news sites about the COVID-19 pandemic in an acute public health crisis, in the releases that include the statement of the prime minister or minister of the Government of the Republic of Croatia in the title, the media frame of economic consequences prevails. -- The discourse of the Government of the Republic of Croatia in an acute public health crisis indicates an increased number of performative expressions. -- In an acute public health crisis, a reactive strategy of rectifying behavior prevails in the communication of the Government of the Republic of Croatia on the Internet. The conducted research indicated a moderate positive correlation between the intensity of the threat and the intensity of communication of the Government of the Republic of Croatia. It is a result that points to the use of deliberate inaction to a certain extent. The Government's online communication during the acute crisis did not predominantly manifest itself through presidentialization. In the largest number of releases by the Government of the Republic of Croatia in the observed period, the media frame of responsibility dominates, and the analysis of the reactive communication strategies showed that in the largest number of cases, the strategy of rectifying behavior is dominant. The discourse used by the Government was based on six “global meanings”, and six “local meanings”, and in the critical period the number of performative expressions increased. As in the case of the Government of the Republic of Croatia, in most of the releases of the news sites, the media frame of responsibility is dominant, and a moderate positive correlation between the agenda of the Government and the agenda of the news sites has been established.