(Reuters) – OPEC oil output fell in November in the first monthly drop since July, a Reuters survey found, as a result of lower shipments by Nigeria and Iraq as well as ongoing market-supporting cuts by Saudi Arabia and other members of the wider OPEC+ alliance.

The Organization of the Petroleum Exporting Countries pumped 27.81 million barrels per day (bpd) last month, down by 90,000 bpd from October, the survey on Wednesday found. Production had risen in the three months to October.

Oil output from OPEC, which has been restraining supply with Russia and other allies since late 2022 to support prices, is set to drop further from next year after OPEC+ agreed to a new round of supply cuts for the first quarter of 2024.

The decline comes despite a further increase in supply from Iran, one of the OPEC members exempt from making cuts. Iran’s output hit another five-year high, the survey found, offsetting some of the cutbacks elsewhere.

Output from the 10 OPEC members that are subject to OPEC+ supply cut agreements fell by 130,000 bpd, the survey found. Saudi Arabia and other Gulf members maintained strong compliance with agreed cutbacks and extra voluntary reductions.

The biggest drop was in Nigeria, which exported fewer barrels in November, as well as declines in Iraq, the United Arab Emirates and Angola, the survey found.

“The export programme was strong but actual supply did not deliver,” said a source who monitors OPEC output in reference to Nigeria, which has still posted a production recovery after seeing declines because of under-investment and unrest.

At a meeting last week, OPEC+ agreed to further output cuts totalling about 2.2 million bpd for the first quarter of 2024 led by Saudi Arabia rolling over its current voluntary cut.

SAUDI STEADY, IRAN UP

Saudi Arabia kept November output close to 9 million bpd, the survey found, as the top exporter extended a voluntary 1 million bpd output cut to provide extra support for the market.

Among those showing higher output, the biggest rise was in Iran where production hit 3.2 million bpd in November, the highest since 2018 when Washington re-imposed sanctions on Tehran, Reuters surveys and separate figures from OPEC show.

Iran’s exports have been rising in 2023 despite U.S. sanctions. Analysts have said the higher exports appear to be the result of Iran’s success in evading U.S. sanctions and Washington’s discretion in enforcing them.

OPEC’s output is still undershooting the targeted amount by almost 700,000 bpd. A revision of output targets for 2024 should bring actual output closer to the target level.

The Reuters survey, which aims to track supply to the market, is based on shipping data provided by external sources, Refinitiv Eikon 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.