OPEC slashed production in December, delivering a signal to the market one month before the producer group officially began a fresh round of output cuts.
Top oil exporter Saudi Arabia was the driving force behind the headline decline. The kingdom's output plunged by 468,000 bpd to just over 10.5 million bpd last month, independent figures show. Data supplied directly by Riyadh show a 450,000 bpd drop to slightly more than 10.6 million bpd.
Output in Libya fell by 172,000 bpd to 928,000 bpd in December, after a group of armed protests and aggrieved workers took over the country's largest oil field.
In Iran, production dropped by another 159,000 bpd to just under 2.8 million bpd, as the nation enters a second month under wide-ranging US. sanctions. The Islamic Republic has gone from being OPEC's third largest producer to its fifth largest, falling behind the United Arab Emirates and Kuwait in December.
Iraq saw the largest jump in production in the final month of the year. It's output rose 88,000 bpd to just over 4.7 million bpd. At that level, Baghdad would need to cut about 200,000 bpd in January to meet its quota under the supply cut agreement. Iraq, OPEC's second largest producer, regularly pumped above its quota through the group's last round of supply cuts.
December marks OPEC's first monthly report since Qatar left the organization amid an ongoing blockade against the Gulf nation by neighbors including Saudi Arabia and UAE.