New York's main contract, light sweet crude for delivery in August, fell 19 cents to USD 96.01 a barrel. Brent North Sea crude for August delivery shed 39 cents to USD 117.94.
Crude prices were still reeling from an unexpectedly dismal US jobs report released on Friday, said Ker Chung Yang, commodity analyst for Phillip Futures in Singapore.
"Last Friday the crude oil prices ended lower after the dismal jobs report... The US jobs growth is weaker than expected," he told AFP.
Data released by the US Labor Department showed the US economy created a paltry 18,000 jobs in June, far worse than expected and not even enough to keep up with population growth.
That pushed the unemployment rate up to 9.2 per cent, and signalled that growth in the world's largest oil consumer remained almost stagnant during the second quarter after a poor first quarter.
Rocketing inflation rates in China, which announced Saturday that its consumer price index hit three-year highs last month, also worried crude traders, Ker said.
"This will prompt some guessing that China will crack down on inflation again," he stated.
China has in the past few months tightened its monetary policy to rein in inflation, but some analysts are concerned Beijing may go too far and trigger a sharp slowdown in the world's biggest energy consumer.