Samsung Group Chairman Lee Kun-hee said Tuesday he will step down from his post at the top of South Korea's biggest conglomerate following his indictment on tax evasion charges.

"I have decided to resign from the post of chairman," Lee told a news conference less than one week after he was indicted following a special independent counsel investigation into the conglomerate's operations.

"We, including myself, have caused troubles to the nation with the special probe," Lee said. "I deeply apologize for that, and I'll take full responsibility for everything, both legally and morally."

After Lee spoke, Vice Chairman Lee Hak-soo, considered the chairman's closest confidante, also announced his resignation as well as that of Lee Jae-yong, the chairman's son and heir who is an executive at Samsung Electronics Co.

Special prosecutors Thursday indicted Lee on charges of evading 112.8 billion won (US$ 113 million) in taxes, ending a three-month probe in the family-run conglomerate prompted by allegations of wrongdoing by a former Samsung lawyer.

Prosecutors, however, dismissed the most explosive claim - that Samsung used affiliates to raise a slush fund to bribe influential South Koreans - for lack of evidence.

They also decided to indict Lee without arrest, saying his apprehension was too big a risk for South Korea, citing "the extremely competitive global economic situation."

Besides Lee, nine other Samsung executives were indicted.