In late afternoon London deals, Brent North Sea crude for delivery in March dropped 55 cents to USD 48.29 a barrel.
US benchmark West Texas Intermediate for February sank USD 1.97 to trade at USD 46.72 per barrel.
"Oil prices fell back ... Dented by the global demand outlook suggested by the IMF," said Jasper Lawler, analyst at CMC Markets.
The International Monetary Fund on Tuesday sharply cut its forecast for global economic growth this year to 3.5 percent, on the back of weaker momentum in nearly all leading economies but the United States.
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Both estimates were 0.3 percentage points lower than in the IMF's previous World Economic Outlook forecasts in October, and underscored the steady deterioration of the economic picture for many countries.
"Crude oil prices remain under heavy pressure with WTI front month futures retreating ... Following news that the IMF cut its global growth forecast by most in three years," added Sucden analyst Myrto Sokou.
"Brent front month futures fluctuated ... Amid concerns regarding a further slowdown of global oil demand."
"We see no near-term catalysts that would change the supply/demand equation," credit ratings firm Moody's said in a market commentary.
It said the drop in crude prices by more than half between June last year and this month reflected an increase in US production, a slow rise in worldwide demand and oil kingpin Saudi Arabia's decision "not to keep acting as OPEC's -- and the world's -- swing producer".
Saudi Arabia is the major producer in the Organization of Petroleum Exporting Countries (OPEC) cartel, which decided in November to leave crude output unchanged, further pressuring prices.
It also lowered its price assumption for WTI to USD 52 a barrel through this year and to USD 62 in 2016.