Prosecutors on Friday raided the offices of Kumho Asiana group, which has been accused of providing illicit support to its subsidiaries.

The fair trade division at the Seoul Central District Prosecutors Office sent prosecutors and investigators to the group's headquarters and an Asiana Airlines office in Seoul and secured account books and computer files.

The latest probe comes after the Fair Trade Commission brought charges against Kumho Asiana in August.

The trade watchdog believes the conglomerate illegally supported Kumho Buslines using its other affiliates, such as Asiana Airlines, and had issued a correction order along with 32 billion won in fines.

The commission also filed a complaint with the prosecution against Kumho Industrial, Asiana Airlines, former group chairman Park Sam-koo and two executives serving in the group's strategic management office at the time.