Brent maintained its 1.5% losses in American trade, resuming the losses after a hiatus on Friday and nearing three-week lows on oversupply concerns, after OPEC plus raised output by 2 million bps this month.
Brent lost 1.5% to $42.90 a barrel, after rising 0.8% on Friday away from July 10 lows at $41.41.
Oil prices rose about 3% in July, the third monthly profit in a row on hopes of global demand recovery.
However, a surge of 2 million bpd in output by OPEC plus producers raised concerns on global oversupply and balance.
The first stage of the May deal stated a cut of 9.7 million bpd until July, with the cut reduced to 7.7 million bpd from August to December, and the third stage will see cuts down to 5.7 million bpd until April 2022.
As output increases, demand continues to struggle in countries where Covid 19 still propagates.
Otherwise, Saudi Arabia and other Arab Gulf countries ended voluntary limits on supplies outside the global deal.