HONG KONG — Chinese regulators said on Wednesday that they had found 12 Japanese auto parts and bearings manufacturers guilty of conspiring to rig prices in the Chinese market, and had imposed a total of $200 million in antitrust fines on 10 of them.

The fines, a record for China's increasingly vigorous enforcement of antitrust laws, is also notable for being levied exclusively against Japanese companies. It coincides with deteriorating diplomatic relations between Tokyo and Beijing over territorial disputes and how events in World War II are remembered and commemorated.

The case involves eight Japanese auto parts makers and four bearings manufacturers. One of the auto parts manufacturers, Hitachi Automotive Systems, and one of the bearings manufacturers, the Nachi-Fujikoshi Corporation, were exempted from fines because the Chinese regulatory agency, the National Development and Reform Commission, said that they had reported monopolistic agreements to the authorities and provided evidence.

The commission, China's top economic policy agency, clearly signaled in a news release announcing the fines that it was engaged in further antitrust cases.

"The National Development and Reform Commission will pursue clues of other illegality that were found during this investigation, as it continues to carry out investigations to ensure fair enforcement, maintain fair competition in the market, protect the legitimate rights and interests of operators and consumers and create a favorable environment for economic and social development," the release said.

A few of the Japanese companies began stepping forward on Tuesday to acknowledge that they had incurred fines. The Japan Auto Parts Industries Association said on Wednesday that it did not yet have a statement on the fines, but might later.

The scale of the fines, and the decision to impose them on entirely foreign companies, underline the Chinese government's eagerness this summer to pursue antitrust cases, often with an emphasis on challenging multinational companies. Many global companies have reaped substantial profits in China and captured market shares that are the envy of local competitors, although the multinationals have also transferred considerable technology and skills and created millions of jobs, sometimes accompanied by large-scale layoffs in their home markets.

The antitrust crackdown has coincided with a sharp slowdown in foreign direct investment in China, which fell 17 percent in July from a year earlier. For the first seven months of this year, however, foreign direct investment in China is down only 0.4 percent.

The National Development and Reform Commission is separately investigating numerous foreign automakers, trying to determine whether they colluded with dealers to compel customers to buy expensive replacement parts from the automakers' own factories, instead of allowing customers to choose replacement parts from independent parts manufacturers.