Prosecutors raided the headquarters of the South Korean unit of U.S. carmaker General Motors Co. on Wednesday as part of an investigation into alleged irregularities committed by its labor union.

The Incheon District Prosecutors' Office said it confiscated accounting books, documents and computer hard discs from GM Korea Co.'s headquarters located in Incheon, 40 kilometers west of Seoul.

They also arrested a 57-year-old company executive in charge of labor management on suspicions of malpractice and receiving bribes.

Prosecutors suspect that the executive, whose identity was withheld, collaborated with union leaders to give favors to a certain company when purchasing gifts for employees, in return for money.

Prosecutors previously indicted two former executives of the labor group for similar allegations.

An official from the company declined to comment on the issue, saying the investigation is under way. (Yonhap)