London: World oil prices slid Tuesday on the eve of vital talks between major powers and key crude producer Iran over Tehran`s disputed nuclear programme, dealers said.
New York`s main contract, West Texas Intermediate for delivery in December, dropped 20 cents to $92.83 a barrel.
Brent North Sea crude for January shed 14 cents to stand at $108.33 a barrel in London midday deals.
Dealers are awaiting Wednesday`s meeting in Geneva on Iran`s disputed nuclear programme after efforts to clinch a deal earlier this month failed.
The United States, China, Russia, Britain, France and Germany -- known collectively as the P5+1 group -- will meet Iranian officials to find a way around the deadlock.
"The main event for this week is the Iran/P5+1 negotiations that are starting tomorrow," said analyst Olivier Jakob at the Petromatrix consultancy.
"It is likely that the meeting will result in an agreement between the two parties and while this first interim agreement will be limited in terms of sanction reliefs, it should provide some greater clarity on the schedule for the next steps and the time-frame that we need to consider for some official relief on oil export sanctions."
Western powers accuse major oil producer Iran of using its nuclear programme to develop weapons.
Iran denies the assertion, insisting it is for peaceful purposes, but its economy is suffering from sanctions imposed to push it to the negotiating table.
The oil market fell Tuesday also on expectations that the US Federal Reserve would soon wind down its economic stimulus in the world`s top crude consuming nation, traders said.
Markets were later Tuesday expected to pay close attention to a speech from outgoing Fed boss Ben Bernanke to see if he gives any hints about when the bank will begin winding down its stimulus.
And on Wednesday, the Fed will publish the minutes of the October meeting of its rate-setting Federal Open Market Committee.
"Sentiment was dampened by speculation that the Fed could begin tapering bond buying sooner than anticipated," said analyst Kash Kamal at the Sucden brokerage in London.
The Fed`s $85 billion-a-month bond-buying programme, known as quantitative easing (QE), is aimed at supporting growth of the United States economy.