Once Romanian troops entered Odessa, they established the headquarters of two of their divisions in the local NKVD building. However, the building was mined by the Soviets, who blew it up, killing over 100 members of the Romanian divisional headquarters, including almost 50 officers, paralyzing the activity of the two divisions for two weeks. In reprisal, Ion Antonescu ordered the arrest and massacre of civilians suspected of aiding the Red Army. When it became clear that identifying individuals directly responsible for the incident would be almost impossible, Antonescu ordered the shooting of Jews. The massacre that followed resulted in 19,000 civilians killed, the majority of whom had nothing to do with the military action. A further number of Odessa Jews were deported to ghettos and concentration camps in the northern half of the region.