China announced it will impose “special” fees on American ships owned or leased by U.S. companies, as well as those built in the United States, starting Tuesday, October 14, according to a statement from the Chinese Ministry of Transport.

The fees will be 400 yuan (56 USD) per net ton on American ships arriving in China, increasing to 640 yuan in April, with further annual increases.

The ministry clarified that the “special port fees” apply to each voyage a ship makes to China, not to each port visited, and fees will not be charged more than five times per year per ship.

The fees will take effect on the same day that U.S. ports begin imposing fees on ships operated or built by China upon their arrival in the United States.

This Chinese measure is a response to an investigation launched by the previous U.S. administration regarding China’s shipbuilding sector.

A spokesperson for the Chinese Ministry of Transport described the fees as a “legitimate measure to protect the legal rights and interests of Chinese shipping companies,” adding that China urges the U.S. side to immediately correct its wrongful practices and stop its unjustified suppression of the Chinese shipping industry.