Oil prices slipped for a second straight day on Tuesday as a slowing global demand outlook outweighed OPEC's deal with associated producers last week to deepen output cuts in 2020.
Brent crude was down 33 cents, or 0.5%, at $63.92 per barrel by 1134 GMT while West Texas Intermediate oil was 29 cents, or 0.5%, lower at $58.
73 a barrel.
The benchmarks fell 0.2% and 0.3% respectively on Monday.
Last week, the Organization of the Petroleum Exporting Countries (OPEC) and associated producers like Russia agreed to deepen output.