In morning trade, New York's main contract, light sweet crude for May delivery, dropped 89 US cents to $US99.97 per barrel.

 

The contract closed at $US100.86 yesterday during floor trading at the New York Mercantile Exchange.

 

London's Brent North Sea crude for May delivery fell 96 US cents to $US98.90, after settling at $US99.86 yesterday.

 

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

 

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.

 

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.