Top U.S. and Chinese officials were meeting in London on Monday to try to defuse a trade dispute that has widened from tariffs to restrictions over rare earths, threatening a global supply chain shock and slower economic growth.

U.S.-China trade talks in London this week are expected to take up a series of disputes that have buffeted relations.

As U.S. and Chinese negotiators meet for trade talks, a primary concern for Washington will be whether Beijing eases the flow of rare earth materials.

Oil prices rose to a seven-week high on Wednesday as markets assessed the outcome of U.S.-China trade negotiations, while pessimism over U.S.-Iran nuclear talks also provided support. Brent crude futures were up 82 cents,