Some of the world's most powerful oil producers had been expected to convene on Thursday, with energy market participants closely monitoring whether the influential group will officially agree to extend their deepest ever round of output cuts.
OPEC kingpin Saudi Arabia and non-OPEC leader Russia were thought to support a one-month extension of the current level of supply cuts, Reuters reported on Wednesday, citing unnamed OPEC sources.
However, the date of a virtual meeting to finalize an agreement was still unclear on Thursday afternoon.
OPEC and non-OPEC allies, sometimes referred to as OPEC+, were originally scheduled to review their production cuts on June 9-10.
Late last month, Algeria, which currently holds the rotating OPEC presidency, proposed this meeting should be brought forward to Thursday.
An OPEC+ meeting was still possible this week, according to Reuters, citing unnamed OPEC sources, if Iraq and other non-complying members promised to deepen their production cuts.
Brent crude futures traded at $39.50 a barrel during early afternoon deals, down more than 0.6%. The international benchmark rose above $40 a barrel for the first time since March 6 in the previous session, before erasing those gains amid OPEC+ uncertainty.
U.S. West Texas Intermediate (WTI) crude futures stood at $36.78 a barrel, almost 1.4% lower. The contract also climbed to its highest level since early March on Wednesday.
Oil prices have marched higher in recent weeks, recovering from a dramatic fall in April which saw Brent futures hover close to 20-year lows and WTI tumble into negative territory for the first time in history.
It comes amid optimism about an economic recovery in China, the world's second-largest economy, and as other countries across the globe seek to gradually lift coronavirus lockdown measures.
Martijn Rats, chief oil analyst at Morgan Stanley, told CNBC's "Squawk Box Europe" on Thursday that oil supply had adjusted "very, very quickly" in order to help the market rebalance.
"A lot of that supply side adjustment has come from OPEC, so if OPEC were to unwind these cuts, release more barrels to the market, we could very quickly end up back in a much weaker situation," Rats said.
"We know prices can go exceedingly low in that weak situation, so from that perspective it is important that OPEC represents a relatively cohesive and united front," he continued. "Quite often, with these production agreements, if only one or two or three of the players start to deviate then it has this habit of sort of falling apart altogether. So it is important that OPEC continues to exhibit a degree of cohesion."
In April, OPEC+ agreed to a cut oil production by a record 9.7 million barrels per day (b/d). The move was designed to prop up prices as the coronavirus pandemic led to an unprecedented collapse in oil demand.
The production cuts began on May 1 and are set to run through to the end of June. Under the current deal, the cuts will then be tapered back to 7.7 million b/d from July through to the end of 2020, and 5.8 million b/d from January 2021 through to April 2022.
Saudi Arabia and Russia's reported plan would see the 9.7 million barrel a day cut extend to the end of July.
Karen Kostanian, an oil and gas analyst at Bank of America Global Research, described Saudi Arabia and Russia as the "central banks of oil" at present, saying oil prices cannot be supported in the absence of a "coherent" agreement between them.
Speaking to CNBC's "Squawk Box Europe" on Thursday, Kostanian said the broader energy alliance of OPEC and non-OPEC partners "understand that the oil markets are expecting them to extend the agreement by at least some measure."
"So, I think that a realistic expectation would be an extension of this agreement by one month or two on the deeper side. But, I think that Russia and Saudi Arabia will stick to the baseline agreement beyond that," he added.
Analysts at S&P Global Platts said in a research note published Wednesday that Brent crude prices "may find some pockets of support" in the range of $35 to $40 a barrel in June.
The commodity pricing agency explained its forecast was based on a supply shut-ins peak, recovering demand and the assumption that OPEC+ maintains discipline at their June meeting.
Looking further ahead, analysts at S&P Global Platts said they expect Brent crude prices to fall back to an average of $35 a barrel in August, citing an oil market "overhang of 1 billion barrels in surplus inventories, supply returns from shut ins, seasonal demand wanes, and anxiety on demand grows heading into the Fall."
"Ample spare capacity and the potential return of disrupted barrels also weigh on markets," they added.