China has officially started collecting special port fees from U.S.-owned, operated, built, or flagged vessels on Tuesday but said Chinese-built ships would be exempted from the levies, according to state broadcaster CCTV.

The details published by CCTV clarify the specific provisions on exemptions, including for ships built by China, empty ships entering Chinese shipyards for repair, and other ships that are deemed exempted from payment.

Following the announcement, U.S. President Donald Trump said he was raising tariffs on Chinese imports to 100% from November 1 and imposing export controls on critical software in reprisal for China expanding its export limits on rare earth minerals.

The special port fees will be collected at the first port of entry on a single voyage or for the first five voyages within the year, CCTV said, adding that the annual billing cycle will begin on April 17.

Failure to pay the fees will lead to stalled import and export procedures for the ship, the state media said.