As a result of the recent U.S. Section 301 investigation into Chinese intellectual property practices, U.S. Customs and Border Protection (CBP) began enforcing, at midnight on July 6, new 25 percent tariffs on $34 billion in Chinese goods. The new tariffs will be applied to  imports of 800 Chinese products including medical devices and auto parts.  

In retaliation for these measures, the Chinese Ministry of Commerce announced this morning that they would begin enforcing retaliatory tariffs of 25 percent on $34 billion in U.S. goods, including soybeans, cotton, rice, sorghum, beef, pork, dairy, nuts, and produce.
 

The statement from U.S. Customs and Border Protection can be found here.  

The statement from China MOFCOM can be found here.