World oil prices fell about $5 a barrel in Monday's trading as the dollar grew stronger compared to other currencies.
The dollar strengthened after President Bush told the G-8 summit that Washington supports a "strong" dollar.
The price of oil for future delivery fell below $139 at one point, before recovering to finish the day's trading above $141.
That is far below the record-high price of $145.85 a barrel set on July 3 as investors worried about the falling dollar and Middle East tensions.
Falling crude oil prices did not prevent the average U.S. retail price of gasoline from hitting a new record high of $1.08 a liter ($4.11 a gallon) Monday.
Some information for this report was provided by AFP, AP and Reuters.