Oil tankers and container ships will be among the hardest hit should China's port fees targeting U.S. vessels take effect on October 14, according to Jefferies LLC.

Nearly 16% of tankers that carry refined products and 13% of those that transport crude oil could be charged hefty fees under Beijing's latest plan, the Wall Street bank wrote in a note. The levy was announced unexpectedly on October 10, as retaliation against a U.S. proposal to impose a similar port fee on Chinese vessels starting the same day.

"These are enough to create sizable disruption, especially given the magnitude of the fees," analysts including Omar Nokta wrote in the note.

The global shipping industry is scrambling to manage the fallout from Beijing's sudden move, which comes amid a resurgence in trade tensions between the world's two biggest economies. The U.S. port fee, first announced in April, is aimed at shaking loose China's hold on maritime trade and shipbuilding, and is part of U.S. President Donald Trump's aggressive push to skew global commerce to U.S. advantage.

To hit back, Beijing has proposed that U.S. equity shareholding of as little as 25% would constitute a vessel as being American and subject to its port fee -- a detail that one shipowner called "a bombshell."

Several shipowners are rushing to review operational risks while putting provisional bookings on hold, according to shipping executives who asked to remain unnamed because of the sensitivity of the issue. Beijing's announcement has given them little time to adjust, they said.

"We are currently assessing its potential impact on our services calling at ports in China. We will update our customers as soon as further clarification becomes available," container-shipping giant A.P. Moller-Maersk A/S said in a statement.

The industry had already been racing to find workarounds to blunt the blow from the United States Trade Representative's punishing port fees. Now it faces additional challenges from China's retaliation, which could cause penalties to rack up quickly.

For a supertanker, they could amount to around $6.2 million. A Capesize bulk carrier hauling iron ore and coal could be hit by up to $3.8 million in fees, according to shipbrokers. A mid-sized containership could face up to $180 per twenty-foot equivalent unit in extra charges if departing from the U.S. West Coast.

Shipping Faces 'Sizeable Disruption' as U.S., China Spar on Fees