Investing.com - Oil fell by over 1% on Monday after a brief relief from extended losses last month as oversupply concerns still held sway.
U.S. crude was down 52 cents, or 1.25%, at $41.08 at 07:00 ET, while Brent crude shed 1.42% to $42.91.
The build-up in U.S. crude stocks last week coincided with the return to production in Nigeria and Canada.
The number oil rigs operating in the U.S. rose for the fifth week in a low and for the eighth time in the past nine weeks.
The Baker Hughes U.S. rig count released Friday showed an increase of three to 374.
On the demand side, Chinese manufacturing data released Monday proved a mixed bag.
The dollar steadied after sharp losses on weaker-than-expected U.S. Q2 GDP growth.
A weaker dollar underpins demand for oil.