BEIJING -- Samsung and LG, along with four firms from Taiwan were penalized on Friday for manipulating the prices of liquid crystal display (LCD) panels in the Chinese mainland, according to China's top price regulator.

Samsung and LG, two leading LCD panel makers of the Republic of Korea, as well as Chi Mei Optoelectronics, AU Optronics, Chunghwa Picture Tubes and HannStar Display from Taiwan have been fined a total of 353 million yuan (56 million U.S. dollars) for price-rigging between 2001 and 2006, said the National Development and Reform Commission(NDRC).

The commission said that it launched an investigation after receiving multiple complaints since Dec. 2006 about the price-rigging acts involving the six companies.

During the investigation, the firms confessed that they held 53 meetings between 2001 and 2006 to fix the prices of flat panels supplied to the Chinese mainland market. This has harmed the interests of both other LCD suppliers and the consumers, according to the NDRC.

The six companies have reimbursed 172 million yuan that they illegally seized from Chinese TV manufacturers, and they also vowed to extend the free warranty period of their LCD panels for TV producers in the Chinese mainland from 18 months to 36 months, the NDRC added.