CHICAGO (Reuters) - Chinese state-owned firms bought at least 500,000 tonnes of U.S. soybeans on Thursday, traders said, in the first purchases since a U.S. official said last month China had committed to buying an additional 10 million tonnes as part of trade negotiations.

FILE PHOTO: Soy bean seeds are seen in a container at a farm in Gideon, Missouri, U.S., May 16, 2018. Picture taken May 16, 2018. REUTERS/Shannon Stapleton/File Photo

The purchases of at least eight bulk cargoes were for shipment primarily from Pacific Northwest grain export terminals from June to September, two traders with knowledge of the deals told Reuters.

A third trader said that purchases totalled at least 15 cargoes, or around 1 million tonnes.

U.S. Agriculture Secretary Sonny Perdue said on Twitter on Feb. 22 that China had committed to buying an additional 10 million tonnes of U.S. soybeans during trade talks.

The two nations have levied tit-for-tat tariffs on each other’s goods since last summer in a bruising trade war that has riled commodities markets and shifted global trade flows.

Washington and Beijing have been negotiating a trade agreement since December and have agreed not to raise tariffs further for the time being.

News of Thursday’s sales lifted soybean futures on the Chicago Board of Trade as traders cheered the renewed buying by the world’s top soybean importer following days of rumours that China was shopping for U.S. soy.

“They’ve been sporadically tire-kicking for a few days, checking on prices. They finally pulled the trigger today,” said a U.S. soybean export trader.

Also on Thursday, U.S. Department of Agriculture data showed China bought 65,000 tonnes of U.S. sorghum for the first time since August.

The futures gains in the soy market, however, were restricted by worries that the purchases would hardly dent massive soybean stockpiles in the United States and around the globe as farmers in Brazil, the world’s top soy exporter, are harvesting a bumper crop.

China drastically cut purchases of U.S. agricultural products last summer after slapping steep duties on a raft of U.S. goods in retaliation for U.S. tariffs on scores of Chinese products.

China has booked only about 9.4 million tonnes of the latest U.S. soybean harvest as of the end of February, a fraction of the 27.7 million tonnes booked at the same point a year earlier, according to USDA data.