The falls came after both crude benchmarks early last week hit highs last seen in 2015, but traders said the market had lost some momentum since then.
Speaking at the Abu Dhabi International Petroleum Exhibition Conference (ADIPEC), al-Mazroui said: "My prediction is OPEC will continue to do what it takes to rebalance the market", CNBC reported.
OPEC members are reportedly forming a consensus around extending by nine months their production-cutting deal with other crude exporters, through the end of 2018.
OPEC and other non-OPEC producers will meet on November 30 in Vienna to decide on oil output policy.
Woman Techie Dies After Being Set on Fire by Stalker in Chennai
Indhuja was taken to the Kilpauk Medical College (KMC) hospital in Chennai, where she succumbed to her injuries today morning. Her mother and sister now getting treated in the same hospital, and are said to be in a critical condition.
The exporters reached the deal last December and have already extended the agreement through March 2018.
Throughout the week, prices were also bolstered by rising global demand data and expectations that OPEC and other producing countries will extend a deal to cut output.
In May, Opec producers agreed to extend production cuts for a period of nine months until March, but stuck to production cuts of 1.2 million bpd agreed in November past year.
Oil prices settled mixed on Monday as geopolitical tension in Middle East offsets rising US output.
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And in a nod to a new generation of artists, Bono crooned an a capella version of Stormzy's "Blinded by Your Grace". The best video , claimed by USA rapper Kendrick Lamar , was one of the few awards to be chosen by the MTV team.
On the supply side, tensions in the Middle East raised the prospect of disruptions, traders said, adding it was unclear whether a strong quake that hit Iran and Iraq on Sunday had affected the region's oil production.
The price of Iran's light crude oil in the week ended on November 3 rose $2.59 to stand at $60.04 per barrel, IRIB reported on Sunday.
Bahrain said at the weekend that an explosion that caused a fire at its main oil pipeline on Friday was caused by sabotage, linking the attack to Iran, which denied any role.
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According to the Hudaibya reference, the Sharif family had been accused of setting up Hudaibya Paper Mills Ltd to launder money. Justice Khosa is the judge who gave a verdict of 14 paragraphs regarding Hudaibiya Paper Mills in the Panama Papers.