OPEC oil output rose for a second straight month in September, a Reuters survey found on Monday, led by increases in Nigeria and Iran despite ongoing cuts by Saudi Arabia and other members of the wider OPEC+ alliance to support the market.

Last month, the Organization of the Petroleum Exporting Countries pumped 27.73 million barrels per day (bpd), the survey found, up 120,000 bpd from August. Production in August had risen for the first time since February.

The rise in September was led by Nigeria, which has been battling with crude theft and insecurity in its oil-producing region. Iran, which has been boosting supply despite U.S. sanctions, also pumped more, with output hitting the highest level since 2018.

Output from the 10 OPEC members that are subject to OPEC+ supply cut agreements rose by 80,000 bpd, the survey found. Saudi Arabia and other Gulf members maintained strong compliance with agreed cutbacks and extra voluntary reductions.

(Editing by Sharon Singleton)