Hungary held Northern Transylvania from 1940 to 1944 . In 1940 ethnic disturbances between Hungarians and Romanians continued after some incidents following the entrance of the Hungarian Military , culminating in massacres at Treznea and Ip . After some ethnic Hungarian groups considered unreliable or insecure were sacked/expelled from Southern Transylvania , the Hungarian officials also regularly expelled some Romanian groups from Northern Transylvania . Also , many Hungarians and Romanians fled or chose to opt between the two countries . There was a mass exodus ; over 100,000 people on both sides of the ethnic and political borders relocated . This continued until 1944
Ip
Ip massacre
Northern Transylvania