Chinese authorities at the Port of Dalian have blocked the entry of vessels carrying Australian coal. A spokesperson with the Chinese government-owned Dalian Port Group also announced a new limit on the total amount of foreign coal allowed in for the remainder of the year. This move is just the latest in a series of financial policies the Chinese have made against Aussie coal since the relationship between the countries cooled in 2017. Reuters reports that recently, Chinese customs officials have been intentionally stalling the clearing of Australian fuel shipments.

“The goals are to better safeguard the legal rights and interests of Chinese importers and to protect the environment,” said the Chinese foreign ministry spokesman Geng Shuang, according to Reuters. Geng also claimed the latest actions are “completely normal.”

Although Dalian is one of the largest ports in China and the world, other smaller ports operated by the Dalian Port Group have also joined the ban. Australian coal makes up around 50% of China’s total coal import. The ports will continue to accept coal shipments from Russia and Indonesia, according to Reuters. Although exports to China account for less than 2% of Australia’s total export tonnage, the new ban symbolizes a further souring of relations between the two countries.

“We continue to engage closely with industry on matters of market access. China is a valued partner of Australia and we trust that our free trade agreement commitments to each other will continue to be honored,” said Simon Birmingham, Australia’s Minister for Trade.