China imposed sanctions on five American subsidiaries of South Korean shipbuilder Hanwha Ocean on Tuesday, accusing them of supporting a US government investigation into the shipping industry, as tit-for-tat port fees took effect.

The United States announced in April it would begin applying fees to all arriving Chinese-built and operated ships after a "Section 301" investigation found Beijing's dominance in the industry was unreasonable.

Beijing responded last week by announcing "special port fees" on US ships arriving at Chinese ports. Fees on both sides kicked in Tuesday.

The sanctioned subsidiaries are Hanwha Shipping LLC, Hanwha Philly Shipyard Inc., Hanwha Ocean USA International LLC, Hanwha Shipping Holdings LLC and HS USA Holdings Corp.

The United States' investigation and subse

See Full Page