Labour unrest in oil-rich Nigeria and new threats from al-Qaeda contributed to traders' jitters at a time when global petroleum demand is high and the emergency supply cushion is thin, leaving little room in the event of an output disruption. Analysts said speculative buying by hedge funds and commodity funds also buoyed crude futures, which settled at their highest level since September 1, just days after Hurricane Katrina made landfall. The fear of new supply disruptions outweighs the knowledge that crude-oil inventory levels are at multiyear highs and that winter temperatures in the US have been above-normal, keeping demand for home-heating fuels low. Meanwhile, the Organisation of Petroleum Exporting Countries (OPEC) on Friday lowered its estimate for world oil demand in 2006 by 100,000 barrels a day to 84.83 million barrels a day. When oil prices fell below US$60 a barrel last month, OPEC members talked of a possible need to trim output. But analysts say such a move would be highly unlikely with prices near US$70 a barrel. PIN/AP