SEOUL (REUTERS) - South Korean prosecutors started investigating domestic conglomerates Lotte Group and SK Group as part of a wider probe into a graft scandal that led to Ms Park Geun Hye's removal from the presidency, Yonhap news agency reported on Wednesday (March 15).

Yonhap, citing unidentified sources, said the prosecution suspected improper dealings between Ms Park and the two conglomerates.

A spokesman for the SK Group told Reuters the conglomerate would cooperate with the investigation. Lotte Group could not be immediately reached for comment.

Ms Park, who was ousted from office on March 10, has denied any wrongdoing.

Samsung Group, South Korea's largest conglomerate, is already embroiled in the scandal. Lee Jay Yong, head of the Samsung Group, is on trial over bribery, embezzlement and other charges in connection with the scandal.

Lee, who is being held in jail, has denied all the charges against him. The company has also denied any wrongdoing.