Oil dropped to $83 a barrel on Monday as some Iranian oil exports are expected to keep flowing after the U.S. reimposed sanctions.
The Trump administration is considering waivers on sanctions, a U.S. government official said on Friday.
Brent crude, the international benchmark, was down $1.07 to $83.09 a barrel at 8.17am GMT. It hit a four-year high of $86.74 last week.
US crude was down 93c at $73.41.
US sanctions will target Iran’s crude oil exports from November 4.
Oil also dropped as investors focused on rising output from other producers, such as top exporter Saudi Arabia, to compensate for lower Iranian supplies.