Bangkok: Oil prices fell slightly on Tuesday as investors awaited the results of the US presidential election. (Agencies)
Benchmark oil for December delivery was down 8 cents to USD 85.57 per barrel at midday Bangkok time in electronic trading on the New York Mercantile Exchange.
The contract rose 79 cents to finish at USD 85.65 a barrel on the Nymex on Monday.
Brent crude, which is used to price international varieties of oil, fell 3 cents to USD 107.70 on the ICE Futures exchange in London.
President Barack Obama is fighting for re-election in an extremely tight race with Republican challenger Mitt Romney.
The uncertain outcome of the race for leader of the world's biggest economy has kept trading on financial and commodities markets muted this week.
The economic crisis in Greece is another factor that traders must weigh. The Greek parliament holds a critical vote this week on a new, four-year austerity package that will impose further wage and benefit cuts.
Unions opposed to more austerity measures have called for a 48-hour general strike. Police are bracing for violence in the debt-ridden country, now entering its sixth year of recession.
Lawmakers are expected to pass the measure. If not, Greece could lose vital rescue loans that have kept it afloat since May 2010, raising the threat of bankruptcy and a euro exit.
"It's a big week this week, with the U.S. election and the situation in Greece in particular. So there is the potential for volatility," said Ric Spooner, chief market analyst at CMC Markets in Sydney.
In other energy futures trading in New York: Wholesale gasoline rose 1 cent to USD 2.63 per gallon; Heating oil was almost unchanged at USD 2.983 per gallon; Natural gas fell 1 cent to USD 3.544 per 1,000 cubic feet.
Bangkok: Oil prices fell slightly on Tuesday as investors awaited the results of the US presidential election.