LONDON - OPEC oil output has risen for a third straight month in October, a Reuters survey found on Tuesday, led by increases in Nigeria and Angola and despite ongoing cuts by Saudi Arabia and other members of the wider OPEC+ alliance to support the market.

The Organization of the Petroleum Exporting Countries has pumped 27.90 million barrels per day (bpd), the survey found, up by 180,000 bpd from September. Production in August had risen for the first time since February.

October's rise was led by Nigeria, which has seen a recovery in shipments which have often been hindered by crude theft and insecurity. Angola exported more cargoes and Iran, which has been boosting supply despite U.S. sanctions, also pumped slightly more, the survey found.

Output from the 10 OPEC members that are subject to OPEC+ supply cut agreements rose by 150,000 bpd, the survey found. Saudi Arabia and other Gulf members maintained strong compliance with agreed cutbacks and extra voluntary reductions.

The Reuters survey aims to track supply to the market. It is based on shipping data provided by external sources, LSEG flows data, information from companies that track flows such as Petro-Logistics and Kpler, and information provided by sources at oil companies, OPEC and consultants. (Additional reporting by Ahmad Ghaddar; editing by Jason Neely)