New York's main contract, West Texas Intermediate crude for delivery in May, shed $1.11 to $102.20 per barrel. Brent North Sea crude for May settlement was down $1.00 at $122.43 in the afternoon.
"The market is primarily driven by the US jobs report that showed slow hiring," said Victor Shum, senior principal at Purvin and Gertz international energy consultants in Singapore.
"The hiring numbers were poorer than expected... and we are seeing a selling in oil futures as well as equities," he added.
Despite unemployment in the United States dropping to the lowest rate in more than three years in March, the Labor Department reported Friday that the number of unemployed workers hovered close to 13 million and hiring slowed, a warning sign that its recovery may be in trouble.
The economy created a meagre 120,000 jobs in March, much lower than the 200,000 forecast by economists.
Retail trade employment fell by 34,000 in March, with most of the losses coming from large merchandise stores.
The health of the US economy is closely watched by the market because it is the world's biggest oil consumer.