However, Romania's neighbors were not satisfied with the new borders. Romania relied on regional alliances and protection from France and the United Kingdom at the west. However, soon Nazi Germany defeated France, causing great concern in the country. Since it was already apparent that the West could no longer protect Romania, the Soviet Union occupied Bessarabia, Northern Bukovina and the Hertza region in 1940 after an ultimatum that Romania was forced to accept. The king, Carol II, was alarmed and sought the help of Germany to protect Romania's territory, but it forced the country to cede Northern Transylvania to Hungary and Southern Dobruja to Bulgaria. The king lost all his popularity, causing Ion Antonescu's rise to power. He officially joined Axis and demanded territories from Yugoslavia after its invasion, specifically Banat and the Timok Valley. This, however, never happened. In 1941, the Axis invaded the Soviet Union, allowing the recovery by Romania of its lost territories plus Transnistria, which was placed under civilian administration. Nevertheless, this operation failed, and after the overthrow of Antonescu, Romania changed sides in 1944 and fought against the Axis, thus losing Bessarabia and Northern Bukovina once again to the Soviet Union. This made possible the recovery of Northern Transylvania by the country.