US crude oil futures were at $53.43 per barrel, down 26 cents, or 0.5%, from their last settlement, CNBC reported.
International Brent crude oil futures were at $61.50 a barrel, down 14 cents, or 0.2%.
High US crude oil production, which rose to a record 11.9 million barrels per day late last year, has been weighing on oil markets, traders said.
In a sign that output could rise further, US energy firms last week raised the number of rigs looking for new oil for the first time in 2019 to 862, an additional 10 rigs, Baker Hughes energy services firm said in its weekly report on Friday.
Beyond oil supply, a key question for this year will be demand growth.
Oil consumption has been increasing steadily, likely averaging above 100 million bpd for the first time ever in 2019, driven largely by a boom in China.
However, an economic slowdown amid a trade dispute between Washington and Beijing is weighing on fuel demand growth expectations.
Earnings at China’s industrial firms shrank for a second straight month in December on falling prices and sluggish factory activity, piling more pressure on the world’s second-largest economy, which reported the slowest pace of growth last year since 1990.