South Korea's antitrust watchdog has launched a probe into five carmakers operating in the country for allegedly conspiring to fix prices and engaging in other unfair business practices, government sources said Tuesday. Hyundai Motor, Kia Motors, GM Korea, Renault Samsung Motor and Ssangyong Motor are under investigation on price-rigging charges and other alleged behind-door collusion to maintain their market shares, according to the sources at the Fair Trade Commission (FTC).