Iran, which is allowed to raise output under a deal among members of the Organization of the Petroleum Exporting Countries (OPEC), pumped 30,000 bpd more oil in December, according to a Reuters survey.
OPEC’s oil output in December fell from a record high ahead of a deal to cut production, helped by attacks on Nigeria's oil industry and top exporter Saudi Arabia trimming exports.
The decline, the first since May, occurred despite higher exports from second-largest OPEC producer, Iraq, and a further upward trend in Libyan output.
Supply from OPEC in December fell to 34.18 mbd, from a revised 34.38 mbd in November, according to the survey based on shipping data and information from industry sources.
Iran, OPEC’s third biggest producer, has more than doubled its crude exports, excluding the ultra-light oil condensate, since December 2015.