Qatar will leave OPEC next month in order to focus on gas production, the Gulf state's new Energy Minister Saad al-Kaabi announced in a surprise move on Monday.
Qatar has been a member of OPEC since 1961.
"Qatar has decided to withdraw its membership from OPEC effective January 2019 and this decision was communicated to OPEC this morning," Kaabi told a Doha press conference.
Kaabi, who also heads state-owned Qatar Petroleum, denied however that the move was linked to the feud with Saudi Arabia and its allies.
Qatar would continue to produce oil and seek deals in countries including Latin America's top oil producer Brazil, said Kaabi.
Despite the Qatari denials, some analysts saw it as a "political decision to oppose Saudi Arabia".
Kaabi said gas production would remain the top priority for Qatar.
OPEC had been informed of the decision on Monday ahead of the announcement, Kaabi said, adding he would still attend the organisation's Vienna meeting later this week, his "first and last" as energy minister.
That meeting is expected to set a policy for 2019 and despite Qatar's announcement, oil prices soared on Monday after Russia and Saudi Arabia renewed a pact to cap output on the sidelines of a G20 summit.
While there was no announcement on how much would be cut and for how long, the pact between the world's two biggest crude exporters was cheered Monday by oil traders, with Brent jumping $2.60 to $62.06 and West Texas Intermediate up $2.42 to $53.35.
Amrita Sen, chief oil analyst for Energy Aspects consultants, argued the move would have limited impact.
"Quitting OPEC is largely symbolic for Qatar," he told Bloomberg. "Its oil production has been steady with limited prospects for increases."
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