International benchmark increased to $73.62 per barrel on Monday at 0650 GMT while American benchmark West Texas Intermediate (WTI) rose to $65.44 a barrel.
The U.S. oil rig decline supported higher crude oil prices on Thursday, April 18, which represented the end of last week's trading since European and U.S. markets closed to observe the Good Friday holiday.
The number of oil rigs in the U.S., which indicates the short-term oil production in the country, was down eight to 925 for the week ending April 18, oilfield services company Baker Hughes said Thursday.
Brent oil ended Thursday at $71.95 per barrel -- up 0.46% for the day, and WTI closed the day with a 0.38% gain at $64 a barrel.
Crude oil prices were slightly up during the week with declines in U.S. crude oil inventories and production, in addition to the possibility that OPEC and Russia could ramp up their production in the second half of 2019.
Brent crude posted a 0.5% increase for the week, while WTI gained 0.2% to end last week.
U.S. Secretary of the State Mike Pompeo plans to announce on Monday that the administration will no longer renew Iran sanctions' waivers upon their expiration on May 2. The eight countries that the waivers apply to are Turkey, Japan, South Korea, China, India, Taiwan, Italy and Greece.
In May 2018, U.S. President Donald Trump withdrew the U.S. from a nuclear deal, which was signed in 2015 between Iran and the P5+1 group of nations (the five permanent members of the UN Security Council plus Germany).
Last year, following the sanctions announcement, the Trump administration granted waivers to eight countries including China, India, South Korea, Turkey, Italy, the U.A.E. Japan and Taiwan -- the top importers of Iran's oil.
By Gulsen Cagatay