During World War II, the territory of Romania suffered very significant modifications. In 1940, Soviet Union occupied Bessarabia, northern Bukovina, and Herza region which after the fall of the Soviet Union in 1991, would become part of Republic of Moldova and of Ukraine. Between 1941 and 1944, these territories together with Transnistria, were administered by Romania briefly, as the country was governed by a military dictatorship allied with Nazi Germany. Transnistria consisted of formerly proper Soviet territory between Dniester and Southern Bug rivers. Nowadays, most of it is in Ukraine, with small parts in the Republic of Moldova (current Transnistria). This territory was kept under Romanian military occupation, and was not annexed to Romania consisted of a further 13 counties.