The United States (US) and China on Tuesday will begin charging port fees on ocean shipping firms that move everything from holiday toys to crude oil, making the high seas a key front in the trade war between the world’s two largest economies.

China said it had started to collect the special charges on US-owned, operated, built, or flagged vessels but clarified that Chinese-built ships would be exempted from the levies.

In details published on Tuesday by state broadcaster closed-circuit television, China spelled out specific provisions on exemptions, including for ships built by China and empty ships entering Chinese shipyards for repair.

The China-imposed port fees would be collected at the first port of entry on a single voyage or for the first five voyages within a year, following an annual billing cycle beginning on April 17.

Early this year, President Donald Trump’s administration announced plans to levy the fees on China-linked ships to loosen that country’s grip on the global maritime industry and bolster US shipbuilding.

An investigation during former President Joe Biden’s administration concluded China uses unfair policies and practices to dominate the global maritime, logistics and shipbuilding sectors, clearing the way for those penalties.

The US is scheduled to also begin collecting fees on October 14.

–Reuters–