China slapped a $29 million fine on General Motors for antitrust violations, a sign of the growing tensions between the U.S. and the Asian nation.

The largest U.S. automaker is accused of setting minimum prices on some models in its SAIC General Motors joint venture. The Shanghai Municipal Development & Reform Commission, which imposed the 201 million yuan fine, alleged that GM punished dealers who sold cars for less than the prices set by the Detroit-based automaker. This is the first time China has fined GM, the second-largest foreign carmaker in China by sales.

China-U.S. relations have become strained after President-elect Donald Trump proposed tariffs on Chinese goods, questioned the One-China policy regarding Taiwan and accused the Asian nation of stealing an American naval drone in international waters in the South China Sea. A Communist Party newspaper in November said a “tit for tat” retaliation could follow proposals by Trump for tariffs on the world’s largest trading nation, which had $627 billion in U.S. trade in 2015.

Shares of SAIC Motor Corp. fell 1.2 percent to 23.17 yuan in Shanghai, before the penalty was announced. They have declined 3.3 percent since Dec. 14 when Bloomberg News reported that GM’s joint venture in China was being investigated for possible antitrust violations.

Last year, China fined Daimler AG’s Mercedes-Benz unit $56 million for monopolistic pricing practices. In 2014, the government penalized Volkswagen AG and Fiat Chrysler Automobiles NV for similar practices as well as a dozen parts makers.