BEIJING/SINGAPORE (Reuters) -China's state-owned COFCO bought three U.S. soybean cargoes this week, two trade sources said, the country's first purchases from this year's U.S. harvest ahead of this week's summit of leaders Donald Trump and Xi Jinping.

COFCO purchased about 180,000 metric tons of soybeans for December and January shipment through Pacific Northwest port terminals, the sources said.

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

Benchmark Chicago soybean futures prices jumped this week to their highest in 15 months, rebounding from recent five-year lows on hopes for a U.S.-China trade deal.

China, the world's biggest soy importer, shunned soybeans from the autumn U.S. harvest, switching its demand to South American suppliers amid trade conflict with Washington.

The unusual delay has already cost U.S. farmers billions of dollars in lost sales, after they largely supported Trump in his campaigns for president.