China’s soybean imports in September fell 13.5% from the previous month, customs data showed on Monday, as an epidemic of African swine fever that has slashed China’s pig herd reduced demand for soymeal.

China, the world’s top market for soybeans, brought in 8.2 million tonnes of the oilseed in September, down from last month’s 9.48 million tonnes, according to data released by the General Administration of Customs.

Still, the figure was above 8.01 million tonnes in the same month a year ago, with importers stepping up buying of Brazilian beans on worries of supply shortages amid a festering Sino-U.S. trade war.

“The volume of soybeans crushed in September was relatively small as crush margins and demand for soymeal have fallen due to African swine fever,” said Xie Huilan, an analyst with Cofeed, an agribusiness research firm.

China’s pig herd shrank by 38.7% in August versus a year ago, according to data published by the Ministry of Agriculture and Rural Affairs in early September. Many in the industry believe the reduction could be much larger than official data suggest.

China is also stuck in a trade war with the United States, curbing shipments from traditionally its second-largest supplier of soybeans. Beijing slapped 25% tariffs on a list of U.S. products including soybeans in July last year, in a response to similar measures by Washington.

“The figures were within expectation, as crushers increased imports of quite some beans from South America in August, mainly on worries that the (Sino-U.S.) trade negotiations would not go well,” said Monica Tu, analyst with consultancy Shanghai JC Intelligence Co. Ltd.

In the past few weeks, Chinese importers have bought more U.S. soybeans, following a government waiver on extra tariffs, as part of a goodwill gesture ahead of trade talks between the two countries.

For the first nine months of the year, China bought in 64.511 million tonnes of soybeans, down 7.9% from the same period last year, customs data showed.

U.S. President Donald Trump said on Friday that China had agreed to make purchases of $40-$50 billion in U.S. agricultural goods, as the two sides agreed on the first phase of a deal to end a months long trade war.