NEW : Congo rebels blame Rwandan Hutus for attack , report says . Internally displaced Congolese flee as rebels attack government troops . Comment: U.N. refugee agency : Some 375,000 have been forced from homes in past year .
NEW : Congo rebels blame Rwandan Hutus for attack , report says . Internally displaced Congolese flee as rebels attack government troops . Torrential rain makes refugee movement difficult . U.N. refugee agency : Some 375,000 have been forced from homes in past year .