The group has been withholding 1.2 million bpd and the increased amount represents about 1.7 per cent of global oil output.
OPEC+ on Jan 1 this year cut output by 1.2 million barrels per day (bpd), and in July, renewed the pact until March 2020.
A forecast by the International Energy Agency for slower global oil demand growth post-2025 also weighed on the market.
US crude exports fell nearly 1 million barrels last week to 2.4 million barrels per day.
Traders may be taking profits on oil ahead of uncertainty around macro-economic data and US oil inventory reports.
US West Texas Intermediate (WTI) crude CLc1 had gained 16 cents or 0.3 per cent to USD 52.97 a barrel.
Brent crude futures LCOc1 fell 30 cents, or 0.5 per cent, to USD 59.067 barrel.
Saudi Aramco officials as a matter of policy do not comment on the kingdom’s monthly OSPs.
The company has not given a specific timeline for the resumption of full output.
US crude was down 26 cents, or 0.5 per cent, at USD 54.84 a barrel by 0644 GMT, while Brent was down 6 cents at USD 58.60 a barrel.