Oil prices tumbled more than 2% on Monday as investors worried about a hit to demand from the coronavirus outbreak, which is spreading rapidly outside China.
Brent crude fell by $1.50 or 2.5% to $57.00 a barrel by 2332 GMT. U.S. crude futures fell by $1.26 or 2.3% to $52.12.
Concerns about the coronavirus grew on Sunday after sharp rises in infections in South Korea, Italy and Iran.
South Korea's government put the country on high alert after the number of infections surged to over 600 with six deaths, while in Italy, officials said a third person infected with the flu-like virus had died, as the number of cases jumped to above 150 from just three before Friday.
In the United States, the oil rig count, an indicator of future production, rose for a third straight week. Drillers added one oil rig last week, bringing the total count to 679, the highest since the week of Dec. 20, energy services firm Baker Hughes Co said.