OPEC oil production in May rose by less than expected, as Iraq made deeper cuts to offset earlier overproduction and Saudi Arabia and the UAE delivered smaller-than-planned increases, a Reuters survey revealed Monday.

The Organization of the Petroleum Exporting Countries (OPEC) produced 26.75 million barrels per day (bpd) last month—up 150,000 bpd from April. However, that figure falls short of the 310,000 bpd increase agreed upon by key members of the wider OPEC+ alliance, which includes non-OPEC producers like Russia.

“Saudi Arabia made the largest increase, adding 130,000 bpd,” the survey said. But Iraq’s cuts—made to improve its compliance with OPEC+ quotas—along with lower Saudi exports, limited the overall rise in output.

Under the agreement for May, five OPEC members—Algeria, Iraq, Kuwait, Saudi Arabia, and the UAE—were permitted to collectively raise output by 310,000 bpd. But they only managed an increase of 180,000 bpd, according to the survey.

“The UAE also pumped below its OPEC+ quota,” a source familiar with the matter noted, explaining that the country had fewer commitments under the compensation mechanism.

Despite these moves, outside estimates—including those from the International Energy Agency—suggest some countries may still be producing above their official quotas. “There is a wide range of estimates of output in Iraq and the UAE,” the report stated, “with many outside sources putting the countries’ output higher than the countries themselves.”

The Reuters survey is compiled using data from LSEG, tracking companies like Kpler, and insights from oil industry sources and consultants.

OPEC+ is gradually rolling back some of its recent production cuts, but the group is balancing that with efforts to ensure compliance and prevent oversupply.