Singapore - Crude prices followed equities down in Asian trade on Monday as a strengthening greenback weighed on oil markets, analysts said.
New York's main contract, light sweet crude for delivery in November, shed 99 cents to $78.21 a barrel in the afternoon.
Brent North Sea crude for November delivery dipped 77c to $101.99.
Asian equities led crude markets down as traders flocked to the safe-haven US dollar amid pessimism on the global economy, said Victor Shum, senior principal of Purvin and Gertz energy consultants in Singapore.
"There is a selling in oil futures tracking equities and the strengthening of the US dollar," he said.
"Global markets continue to be concerned about economic growth, especially in Europe and the US... Because of the concern about global markets, there is a flight to safety with investors flocking to the US dollar," Shum added.
Major Asian bourses were sharply down in afternoon trade - with Tokyo and Hong Kong stocks plunging 2.26% and 4.95% respectively - as European debt fears resurfaced after Greece said it would miss its deficit target set for it by the IMF and EU.
The euro slumped to an eight month low against the US dollar on Monday, falling to as low as $1.3311 in intraday trade before recovering some lost ground to $1.3327 at 05:05 GMT. The unit had closed at $1.3451 in the US late on Friday.
A strengthening dollar makes dollar-priced crude more expensive to traders using other currencies.