Oil fell on Wednesday, under pressure from a potential increase in OPEC crude output to cool the market's recent rally and cover any shortfalls in supply from Iran and Venezuela.
Across the broader financial markets, investors dumped equities and other industrial commodities in favor of Japanese yen, U.S. and German government bonds and gold, as concern mounted that setbacks to U.S.-China trade talks would undermine increasingly fragile-looking world growth.
Brent crude futures were last down 56 cents at $79.01 a barrel by 1153 GMT, while U.S. crude fell 41 cents to $71.79 a barrel.
Oil prices have gained nearly 20 percent so far this year, with Brent briefly rising above $80, driven primarily by coordinated supply cuts by the Organization of the Petroleum Exporting Countries and partners including Russia.
The price has also been affected by rising geopolitical tensions that could dent global output just as demand is set to hit 100 million barrels per day in the final quarter of this year, according to the International Energy Agency.
In addition, the United States plans to reimpose sanctions on major oil producer Iran, while an economic crisis has decimated Venezuela's crude output.
Based on the prospect of a shortfall in supply relative to demand, investors had driven their bets on a sustained rise in the price of oil to record highs earlier this year.