Trade disputes between the United States and China are heating up, as Washington complains about Chinese auto parts and Beijing files a complaint about a new U.S. tariff law.

Monday, China went to the World Trade Organization accusing the United States of unfairly raising tariffs on 30 products, including tires and kitchen appliances.

Beijing's action comes as the U.S. Trade Representative has filed a complaint over allegedly improper government subsidies for China's auto industry.

U.S. President Barack Obama is expected to discuss the complaint during a campaign stop in the state of Ohio.

Ohio is home to many autoworkers, and is seen as a vital political battleground in the race between Mr. Obama and his Republican rival Mitt Romney for the presidency.

The Democrats and Republicans have been accusing each other of failing to protect U.S. jobs in dealings with China.

The $350 billion U.S. auto and auto-parts manufacturing industry employs 800,000 workers.