in 1970–71, catholics made up about 36% of the population and about 18% of the udr. by the end of 1972 the number of catholics in the udr had dropped to 3% and never rose above that figure again. there are a number of reasons for this. in the early years of the conflict, relations soured between the catholic community and the army. this was mainly due to incidents such as the falls curfew, internment, bloody sunday and operation motorman. there were also frequent claims of udr soldiers abusing catholics at checkpoints and during house searches. catholic church and irish nationalist leaders withdrew their support for the regiment. many catholic soldiers left the regiment due to pressure and intimidation from their own community, and the ira's policy of singling out catholic soldiers for assassination. catholics within the regiment also reported being intimidated by protestant fellow soldiers. other catholics resigned in protest at what they saw as the army's harsh and biased treatment of their community, especially after operation demetrius (the introduction of internment). the "belfast telegraph" reported that 25% of the regiment's catholics resigned in 1971, half of those in the months following operation demetrius. by the end of 1972, the vast majority had resigned or simply stopped turning up for duty.