Oil prices ended lower on Tuesday amid disagreements over a production cut among OPEC (Organization of the Petroleum Exporting Countries) members.
OPEC agreed last month to cut oil production to 32.5 million barrels a day from current level of 33.24 million barrels a day to boost the market.
The group will agree concrete levels of output by each country at its next formal meeting in November.
Iraqi oil minister Jabar Ali al-Luaibi said on Sunday that the country, second largest producer in OPEC, wanted to be exempt from output curbs as it needed more money to fight Islamic State militants.
The West Texas Intermediate for December delivery lost 0.56 US dollars to settle at 49.96 US dollars a barrel on the New York Mercantile Exchange, while Brent crude for December delivery decreased 0.67 dollar to close at 50.79 dollars a barrel on the London ICE Futures Exchange.
