International Benchmark Brent crude traded at $67.19 per barrel while American benchmark West Texas Intermediate (WTI) saw $63.78 at 06.40 GMT on Monday.
Brent crude traded at $66.19 per barrel while WTI saw $62.14 at 06.40 GMT on Friday.
Brent oil started the week with a price of around $65 last week, and increased to around $66.47 by the end of the week.
The U.S. Energy Information Administration said on Thursday that commercial crude oil inventories in the country fell by 0.4 percent, or by 1.6 million barrels, to 420.5 million barrels, which resulted in an increase in crude oil prices trading above $66. However, the market expectation was an increase of 1.8 million barrels in stocks.
In addition, the number of oil rigs in the U.S. increased by one this week, oilfield services company Baker Hughes data showed on Friday. With that result, the number of oil rigs, which indicates the short-term change in the U.S.' oil industry, is now at 799. The current level also shows approximately a 33 percent increase in the oil rig count, which stood at 602 during the same period last year.
According to experts, the decline in U.S. crude oil production also supported the upward movement in oil prices. Last week, crude oil production in the U.S. fell by a thousand barrels per day to 10.27 million barrels, compared to the previous week. This decline was the first after increases over five straight weeks.
The statement of a 133 percent conformity level of the Organization of the Petroleum Exporting Countries (OPEC) and participating non-OPEC countries on Thursday also pushed prices to their highest level last week of $66.48.
By Gulsen Cagatay