NEW YORK—U.S. crude oil exports surged 260,000 barrels per day (bbl/d) in June to a monthly record of 3.16 million bbl/d as South Korea bought record volumes and China resumed purchases, data from the U.S. Census Bureau showed on Aug. 2.

South Korea surpassed Canada to become the biggest purchaser of U.S. crude at about 605,000 bbl/d. China purchased about 292,000 bbl/d, the most since June last year and was the third-largest buyer of U.S. crude in June, the data showed.

China, once the top buyer of U.S. crude, had slashed its purchases last year as a trade war between the world’s two largest economies has dragged on.

U.S. President Donald Trump stunned financial markets on Aug. 1 by saying he plans to levy the additional duties beginning on Sept. 1, marking an abrupt end to a truce in a year-long trade war that has slowed global growth and disrupted supply chains.

U.S. crude exports have surged since an export ban was lifted in late 2015, with shipments reaching 30 countries in June.

Other top buyers in June were Canada, with about 311,000 bbl/d and India at 290,000 bbl/d, followed by Netherlands, which took in about 274,000 bbl/d.

India, the world’s third-biggest oil importer, has stepped up U.S. crude purchases after Washington imposed sanctions on Tehran in November.

The Trump administration renewed sanctions against Iran last year over its nuclear program, although some buyers were allowed to continue taking limited volumes of Iranian oil under a six-month waiver. In May, the United States ended those exemptions.