BEIJING (AFP) — China said Friday it would impose “special port fees” on ships operated by and built in the United States (US) after Washington announced charges for Chinese-linked ships in April.

Incremental fees will be collected at Chinese ports from 14 October, the transport ministry said in a statement.

US ships arriving in China will be charged 400 yuan ($56) per net ton. That fee will go up to 640 yuan in April and then increase annually.

The “special port fees” apply to each ship’s China voyage — not at each port — and a vessel will be charged no more than five times a year, the ministry said.

The charge takes effect the same day US ports begin applying fees for Chinese-built and operated ships arriving there.

That move stemmed from a probe into China’s shipbuilding sector launched under the previous US administration.

A transport ministry spokesperson called Beijing’s levies a “legitimate measure to safeguard the lawful rights and interests of Chinese shipping companies.”

“We urge the US side to immediately correct its wrongful practices and cease its unwarranted suppression of China’s shipping industry,” the unnamed spokesperson said in a separate statement.