Waiting times for commodity vessels queued off China’s ports increased to the lengthiest this year, as the geopolitical sparring between Beijing and Washington disrupts global trade.

It took an average of 2.66 days for a vessel to get into a berth after arrival in the week to October 19, according to Bloomberg calculations based on data from ship-tracking platform Kpler. That’s an increase of 17% on-week, and the longest period this year, the calculations show.

China is the world’s largest commodity importer, and vessel snarls — if prolonged — could ripple through the global supply chain, affecting liquid cargoes such as crude, as well as bulks like iron ore. Beijing and Washington have sparred over shipping, with China introducing a hefty extra fee on vessels known to have American links, following a similar U.S. move. The maritime friction forms one part of the nations’ larger trade dispute.

In addition, Washington also imposed sanctions on a major oil-import terminal operator in China’s east, Rizhao. That move was the latest in a long line of moves aimed at frustrating shipments of crude oil from Iran to China.

Some oil hubs have seen wait times lengthen as tanker owners sought to comply with the new directives. Ships at Dongjiakou waited an average of 2.79 days last week, the second-highest period in Kpler figures. Those at Yantai, meanwhile, idled for 2.7 days, up from about 1.8 the prior week. 

“Shipowners are thinking they should hold on, and wait until they can enter the port,” said Matt Wright, freight analyst at Kpler. “There is still a great deal of uncertainty surrounding which owners face fees.”

Kpler figures can be subject to revision and updates as more information becomes available.