Oil prices tumbled on Tuesday as investors worried Britain's exit from the European Union would slow the global economy.
Persistent signs of abundant supply despite another militant attack on Nigeria's oil industry also weighed on markets.
Brexit worries hit Britain's property market and drove the pound to a 31-year low. A flurry of data from China in the coming weeks is expected to show weakness in trade and investment.
Traders said oil prices were also pressured by data from market intelligence firm Genscape showing a build of 230,025 barrels at the Cushing, Oklahoma storage hub for U.S. crude futures, during the week to July 1.
"There are risk-off trades across the board," said David Thompson, executive vice-president at Washington-based commodities broker Powerhouse. "Stocks, commodities, sterling are all off while U.S. bond and T-bills are soaring."