(Bloomberg) -- OPEC’s crude output edged higher last month as Nigeria partially reversed a long-term slump by cracking down on oil theft.

The Organization of Petroleum Exporting Countries boosted supplies by 150,000 barrels a day, with the West African nation effectively providing the entire gain, according to a Bloomberg survey. Total group output was 29.14 million barrels a day.

Nigeria has revived crude production from record lows by hiring security companies linked to Government Ekpemupolo, a onetime warlord in the oil-producing Niger River delta region. State-owned Nigerian National Petroleum Co. aims to build on the progress, Lagos-based newspaper ThisDay reported last month. 

But even with December’s gains, which have bolstered Nigerian production to 1.35 million barrels a day, the country’s output is still barely half the level pumped a decade ago. 

Elsewhere in the organization, producers were sticking to the production curbs agreed late last year to keep global markets in balance. Key members Saudi Arabia, the United Arab Emirates and Iraq kept supplies roughly unchanged, with the Saudis pumping 10.48 million barrels a day.

OPEC and its allies, a 23-nation bloc known as OPEC+, agreed to collectively reduce supplies by 2 million barrels a day from November, and then hold steady for the rest of this year. 

While the decision initially drew a fierce rebuke from the White House, it appears to have helped stabilize world markets against fears of recession in the US and a shaky economic reopening in China. Oil futures traded near $83 a barrel in London on Tuesday.

Outside of OPEC’s Middle East giants, other members are, like Nigeria, struggling with under-investment and operational disruptions. Fellow African exporter Angola is showing particular signs of strain. As a result, the 10 OPEC nations bound by quotas are pumping about 650,000 barrels a day below their collective target.

Supplies from the wider OPEC+ coalition are set to come under pressure after further European Union sanctions came into force last month on member nation Russia, as punishment for its invasion of Ukraine. 

A panel of ministers from the OPEC+ coalition will hold a monitoring meeting to review production policy on Feb. 1.

Bloomberg’s survey is based on ship-tracking data, information from officials and estimates from consultants including Kpler Ltd., Rapidan Energy Group, Rystad Energy and SVB Energy International LLC.

--With assistance from Anthony Di Paola, Brian Wingfield, Lucia Kassai, John Deane, Prejula Prem and Verity Ratcliffe.

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