A military group that rules another country by force is

A military group that rules another country by force is a junta.

A military group that rules another country by force is called a military junta.

Explanation:

A military junta is a government made up of high-ranking commanders of the armed forces of a country, usually after the seizure of power by a coup d'état. The junta may be directly in charge of the functions of government or nominally exercise a consultative role, delegating the specific political office to one of its members and another representative.

Unlike the charismatic dictatorships, centered on a strongly personalized leader, the boards respond in general to situations of strong political instability, where ideological interests lead the most conservative sectors to take action directly; The Cold War motivated a multitude of military juntas in the 1950s, 1960s and 1970s, especially in Latin America, Africa and Asia, although it was also common in many European countries. However, in third world countries, especially in Africa, there have also been experiences of military governments motivated by socialist and Marxist ideas and sectors, for example Siad Barre in Somalia or Gaddafi in Libya.