 During the following period, two Romanian volunteer battalions were established by recruiting Romanian soldiers in Bessarabia and the Russian Black Sea ports, as well as workers who had been evacuated to Southern Russia.Between January and March 1918, the volunteers participated along the local Red Guards in battles against the troops of the Ukrainian People's Republic, the regular Romanian Army which had occupied Bessarabia, as well as against the Central Powers armies advancing from the Northwest.The occupation of Odessa by Austro-German troops in the aftermath of the Treaty of Brest-Litovsk forced the volunteer battalions to retreat to Crimea and central Russia, with the members of the Action Committee either going underground or leaving for Russian areas still under Soviet control.