Oil slipped towards $57 a barrel today, pressured by concerns about weakening global economic growth and oil demand, as well as by signs of excess supply despite OPEC-led cuts.
Euro zone business growth stalled in September, a survey today showed, a day after the US announced import tariffs on European Union products.
US crude inventories rose 3.1 million barrels last week, more than forecast.
Brent crude fell 62 cents to $57.07 a barrel this afternoon, after tumbling 2% in the previous session.
US West Texas Intermediate (WTI) crude was down 80 cents at $51.84.
Lending oil some support were hopes that the US and China might make progress in resolving their trade dispute and figures showing output in the US - which has been the fastest source of supply growth - fell in July.
This year, Brent has risen about 7%, supported by supply cuts led by the Organization of the Petroleum Exporting Countries and allies including Russia, plus involuntary outages such as a drop in Iranian and Venezuelan exports due to US sanctions.
Nonetheless, concern about the worsening economic outlook has overshadowed support from the supply side and the prospect of further output disruption in the Middle East appears of limited concern to investors.
Brent spiked to $72 a barrel on September 16 following attacks on Saudi Arabian oil installations that shut more than half of the country's output.
But it is now below the pre-attack level after the Saudi authorities resumed output.