China's state-owned COFCO bought three U.S. soybean cargoes, two trade sources said, the country's first purchases from this year's U.S. harvest, shortly before a summit of leaders Donald Trump and Xi Jinping, Reuters reported.

As the two nations battle over trade tariffs, the lack of Chinese buying has cost U.S. farmers billions of dollars in lost sales, after they largely supported Trump in his campaigns for president.

Although COFCO's deal for December-January shipment of about 180,000 metric tons of soybeans was China's first such buy in months, traders do not expect a significant resumption in demand for U.S. cargoes after recent large South American purchases, according to Reuters .

COFCO did not immediately respond to a Reuters request for comment.