Crude oil prices fell as the dollar strengthened and Saudi Arabia said it was working to expand production.
Saudi Arabia says it is investing in its oil infrastructure to boost output
At one point US light sweet crude fell to $100.02 per barrel in Asian trade. In New York it later closed at $100.86.
Commodities, including oil, have been sensitive to changes in the dollar's value and the latest rebound for the dollar has weakened oil prices.
Also Saudi Arabia said on Sunday that it is investing in oil infrastructure to help meet future demand.
Saudi Arabia has been under pressure from the US to help ease soaring oil prices.
On Saturday US Vice-President Dick Cheney met Saudi leaders in Riyadh to discuss oil prices.
On Sunday the Saudi, the Supreme Council of Petroleum and Mineral Affairs said in a statement: "The kingdom will work with OPEC countries, other producers and consuming countries towards oil market stability and to avoid the effects of harmful speculation."
Analysts say that speculators, who have helped drive up the price of oil, are taking the opportunity to cash-in on their gains.
"I think there's still a lot of profit taking in the market and that is pushing down oil prices," said Tetsu Emori, a fund manager at Astmax in Tokyo.
"The US dollar is also bouncing back from major currencies, so that's adding to the downward pressure."