Crude oil prices edged lower Monday as traders remained cautious ahead of a looming US \"fiscal cliff\" and as Greece awaits an EU decision on release of a loan installment to avoid default. West Texas Intermediate for December shed 50 cents from Friday\'s closing level to end the session at $85.57 a barrel. In London trade, Brent North Sea crude for delivery in December fell 33 cents to $109.07 a barrel. \"The crude complex remains at the mercy of developments and non-developments\" in two areas that are currently dictating focus, \"the impending \'fiscal cliff\' and the euro debt crisis,\" said Matt Smith at Summit Energy. The US Congress remained divided after last week\'s elections, with Democrats holding the Senate and Republicans the House of Representatives, underlining challenges in reaching compromise to avoid the year-end \"fiscal cliff\" of spending cuts and tax hikes expected to tip the economy back into recession. Greece also was a front-burner worry for the market, as eurozone finance ministers debate whether Athens has met conditions set by its international creditors to provide bailout funds to avert a disastrous sovereign default. Tensions in the Middle East, especially in Israel, had slowed the fall in oil prices, Summit\'s Smith said. Israel said its troops fired tank shells into Syria on Monday, confirming \"direct hits\" on the source of a mortar round that struck the Golan Heights as tensions flared along the ceasefire line. Oil prices were also hit by news that Japan\'s economy shrank in the July-September quarter, but losses were capped by evidence of strong energy demand in Asian powerhouse China. Traders said the market also pushed lower after the International Energy Agency projected the United States would become the world\'s top oil producer by 2020. \"Even though the market rarely reacts much to the long-term IEA outlook, it definitely weighs that the organization is getting increasingly optimistic with regards to US tight oil production,\" said SEB analyst Filip Peterson.