In afternoon trade, New York's main contract, light sweet crude for May delivery, dropped 51 US cents to US$100.35 per barrel.

The contract closed at US$100.86 on Monday during floor trading at the New York Mercantile Exchange.

London's Brent North Sea crude for May delivery fell 948US cents to US$99.38, after settling at US$99.86 on Monday.

'The recovery in the US dollar has simply put downward pressure on oil prices,' said Victor Shum, a Singapore-based analyst with energy consultancy Purvin and Gertz.

The US currency has recovered significantly after falling to a lifetime low of 1.5905 to the euro more than a week ago. Surprising US home sales data also provided a boost.

The euro was trading at US$1.5432 in morning Asian trade.

A weaker US currency encourages demand for dollar-priced oil because it becomes cheaper for buyers using stronger currencies, while investors also seek to guard against risks to inflation.

Investors are also extremely cautious in their outlook for the US economy, which has been roiled by the subprime mortgage sector's meltdown. Some analysts believe the world's biggest economy is already in a recession.

US energy demand is likely to slow if economic growth weakens. -- AFP