Equities on Wall Street and in Europe fell with oil prices after Opec downgraded its forecast for 2015 global demand to the lowest level in 12 years, while Saudi Arabia's oil minister maintained the nation's resistance to cutting output.
"Why should we cut production? Why?" Saudi Oil Minister Ali al-Naimi told journalists on the sidelines of an annual UN climate change conference in Lima, Peru, Reuters reported.
Separately, the Organisation of Petroleum Exporting Countries downgraded its prediction for global demand next year, cutting it by about 280,000 barrels a day to 28.92 million a day from its previous estimate.
Oil slumped to fresh five-year lows. Brent crude sank as much as 4.9 per cent to US$63.56 a barrel on the ICE Futures Europe Exchange in London.
In afternoon trading in New York, the Dow Jones Industrial Average dropped 0.81 per cent, the Standard & Poor's 500 Index slid 0.78 per cent, while the Nasdaq Composite Index fell 0.65 per cent.