Crude oil prices tumbled to a new 17-month low below $62 a barrel yesterday, driven down by a gloomy assessment of the world economy, but later bounced back above the $63 level.

Crude oil prices tumbled to a new 17-month low below $62 a barrel yesterday, driven down by a gloomy assessment of the world economy, but later bounced back above the $63 level.

US light, sweet crude for December delivery fell as low as $61.30 a barrel before recovering. It later closed 93 cents down at $63.22 on the New York Mercantile Exchange.

North Sea Brent crude was 93 cents lower at $61.12 in London dealing.

Gloomy assessments about the world economy have had a greater impact on the market than the Opec cartel's deal on Friday to trim output by 1.5 million barrels per day to try to support prices. A recession will reduce global demand for crude.

"What Opec did is constructive, but right now that is beside the point," said Mike Wittner, an analyst at French bank Société Générale.

Oil traders were watching for signs the Organisation of the Petroleum Exporting Countries would implement its cuts.

Asian oil refiners said they had yet to receive notice of any curbs on their Gulf crude oil shipments, but most were expecting a 5% cut.

JBC Energy, a consultancy based in Vienna, said prices were being driven by the present financial crisis and not by Opec cuts.

Oil prices have more than halved from a record high above $147 a barrel in July.

Meanwhile, tensions increased in Sudan yesterday, after kidnappers killed five of nine Chinese oil workers seized in the South Kordofan area.

The Sudanese Foreign Ministry said the kidnappers were members of the Darfur rebel group the Justice and Equality Movement.

China has invested heavily in Sudanese oil.