© Reuters. FILE PHOTO: A view shows branded oil tanks at Saudi Aramco oil facility in Abqaiq, Saudi Arabia October 12, 2019. REUTERS/Maxim Shemetov/File Photo

By Natalie Grover

LONDON (Reuters) -Oil prices were on track for a sixth week of gains after Saudi Arabia and Russia, the world’s second and third-largest crude producers, pledged to cut output through September.

futures for October edged 34 cents higher to $85.48 a barrel by 1228 GMT, while U.S. West Texas Intermediate crude for September crept up 31 cents to $81.86.

Both benchmarks were set for their longest streak of weekly gains this year. Brent has risen 15.4% and WTI by 18.2% during the last six weeks.

Saudi Arabia on Thursday extended a voluntary oil production cut of 1 million barrels per day (bpd) to the end of September, keeping the door open for another extension. Russia has also elected to reduce its oil exports by 300,000 bpd next month.

Meanwhile, a meeting of OPEC+ – the Organization of the Petroleum Exporting Countries and allies – on Friday yielded no additional changes to output policy, sources told Reuters.

“In isolation, oil looks so very good. But we have not traded in isolation for years and although we often like to feel our market is detached from the wider suite, it is not,” said John Evans of oil broker PVM.

“It is a large piece in the puzzle of global markets and while macroeconomic data deliver unfavourable growth signals, the however(s) will continue.”

Those questions came in the form of the latest batch of U.S. data showing tight labour markets and a slowing service sector, raising concerns of an economic slowdown that could curb demand for oil.

“A strong dollar has weighed on crude prices and everyone wants to know if a hot labour market will force the Fed to tighten policy even further,” said Edward Moya, an analyst at OANDA, referring to the U.S. Federal Reserve potentially raising interest rates.

Additionally, the downturn in euro zone business activity worsened more than initially thought in July and the Bank of England raised its interest rate to a 15-year peak on Thursday.

Separately, an overnight Ukrainian naval drone attack on Russia’s Black Sea navy base at Novorossiysk – a civilian port that handles 2% of the world’s oil supply – temporarily halted all ship movements before normal operations were resumed.

(Reporting Natalie Grover in London; Additional reporting by Arathy Somasekhar in Houston and Sudarshan Varadhan in Singapore; Editing by Sharon Singleton and Jason Neely)