Benchmark oil for June delivery was down $1.11 to $94.93 per barrel at late afternoon Bangkok time in electronic trading on the New York Mercantile Exchange. The contract fell 35 cents to close at $96.04 a barrel on the Nymex on Friday.
The stronger dollar is causing oil prices to fall, analysts said. The dollar has risen in recent days against the euro and last week passed the 100-yen mark for the first time in four years.
Since oil is traded in dollars, a stronger dollar makes crude and other commodities less appealing to investors with other currencies.
"This, like the stock market, ends up pulling a lot of money out of commodities and into more reliable risk," said Carl Larry of Oil Outlooks and Opinions in a market commentary.
Brent crude, which is a benchmark for many international oil varieties, fell $1.21 to $102.70 a barrel on the ICE Futures exchange in London.
In other energy futures trading on Nymex:
— Wholesale gasoline fell 3 cents to $2.83 a gallon.
— Heating oil lost 2.6 cents to $2.88 a gallon.
— Natural gas fell 1.6 cents to $3.894 per 1,000 cubic feet.