HONG KONG (AP) — China’s Commerce Ministry said it was banning dealings by Chinese companies with five subsidiaries of South Korean shipbuilder Hanwha Ocean in the latest swipe by Beijing at President Donald Trump’s effort to rebuild the industry in America.

The ministry also announced that it was investigating a probe by Washington into China’s growing dominance in world shipbuilding, and threatened more retaliatory measures. It said the United States probe endangers China’s national security and its shipping industry and cited Hanwha’s involvement in the investigation.

The U.S. Trade Representative launched the Section 301 trade investigation in April 2024. It determined that China’s strength in the industry was a burden to American businesses.

“China just weaponized shipbuilding,” said Kun Cao, deputy chief executive at consulting firm Reddal. “Beijing is signaling it will hit third-country firms that help Washington counter China’s maritime dominance.”

International shipping and shipbuilding are areas of friction between Washington and Beijing. Each side has imposed new port fees on each other’s vessels that took effect this week.

South Korea and the United States have been building closer ties in shipbuilding in response to China’s dominance as the world’s largest shipbuilder.

In late 2024, Hanwha Ocean acquired the Philly Shipyard in Pennsylvania for $100 million. It announced in August that it plans to invest $5 billion in new docks and quays as part of its support for U.S. efforts to restore globally competitive shipbuilding capacity.

Last year, Hanwha Ocean secured contracts with the U.S. Navy to perform maintenance, repair and overhaul work for U.S. naval vessels.

The company said via email that “Hanwha Ocean is aware of the announcement made by the Chinese government and is closely reviewing its potential business impact on the company.”

In a statement to The Associated Press, South Korea’s Foreign Ministry said the Seoul government was assessing how the sanctions might affect the Hanwha companies and related South Korean industrial sectors.

The ministry said it will “communicate with relevant ministries, industry representatives and the Chinese side to minimize damages resulting from these measures.”

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

U.S. businesses represent just 2.9 percent of world fleet ownership by capacity and 0.1 percent of global shipbuilding tonnage.

China accounts for more than half of all new shipbuilding, with South Korea at about 30 percent and Japan just more than a tenth of the total.