Lotte Group says Shin Dong-joo, elder brother of its Chairman Shin Dong-bin, "crossed the line" for announcing that he will sue his younger brother.

Immediately following the elder Shin's announcement, Lotte Group issued a statement Thursday criticizing him for going too far and again using his elderly and ill father, Lotte's founder Shin Kyuk-ho.

Shin Dong-joo said earlier that he received full authority from his father to sue Dong-bin and other executives at the group's parent firm, Lotte Holdings.

Lotte argued the lawsuit will not affect the current situation in any major way as Chairman Shin Dong-bin legitimately secured his management rights through due legal procedures involving the board of directors and a shareholders meeting.

Regarding General Chairman Shin Kyuk-ho's involvement in the litigation, Lotte Group said it cannot help but question whether it is the general chairman's true intention.