Iraq pumped 2.984 million barrels a day in June, outpacing Iran’s 2.963 million, the Organization of Petroleum Exporting Countries’ Vienna-based secretariat said in its Monthly Oil Market Report. That’s the first time Iraq’s output has exceeded Iran’s since 1988, when the countries ended their eight-year war, statistics compiled by BP Plc show.

The reduction from Iran, ahead of full sanctions by the EU that started on July 1, led to the second monthly decline in total OPEC production to 31.36 million barrels a day in June, versus 31.47 million in May, according to the group’s estimates, which are based on secondary sources including analysts and news agencies.

Editor’s Note: Watch URGENT Summit on a Nuclear Iran – Sign Up Here

Falling OPEC production last month coincided with a 4 percent drop in Brent crude on London’s ICE Futures Europe exchange, contributing to a 20 percent price decline for the second quarter.

“Iran and Angola led the crude oil output decrease, while crude oil output from Iraq, Kuwait, and Libya experienced the largest increase in June,” the monthly report said, without elaborating on reasons for the changes.

The organization, provider of about 40 percent of the world’s oil, maintained its official production ceiling at 30 million barrels a day at a meeting in Vienna last month.

Government Data

Saudi Arabia, the world’s largest crude exporter, pumped 9.89 million barrels a day in June, versus 9.88 million in May, according to OPEC’s secondary sources. OPEC also publishes official production figures for some nations as supplied by a “direct communication” from those governments. Saudi Arabia’s official production rate rose to 10.1 million in June from 9.81 million in May, the kingdom said.

Iran’s government didn’t provide June production data to OPEC, though it listed May production at 3.76 million barrels a day, little changed from April.

“Iran is currently producing about 4 million barrels of oil a day,” Deputy Oil Minister Ahmad Qalebani said, according to the Iranian Oil Ministry’s Shana news website. “Decrease in production in certain areas was due to periodical maintenance, which means that the oil production capacity in the country hasn’t decreased,” he said, according to the report.

The rising rate of Iraqi production comes as foreign investors such as Exxon Mobil Corp. and BP Plc are developing new fields and reworking older deposits. The country has held several licensing rounds for oil and gas fields since the U.S.-led invasion of 2003 ended the rule of Saddam Hussein and more than two decades of stagnation caused by wars, sanctions and underinvestment.

OPEC’s 12 members are Algeria, Angola, Ecuador, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, the United Arab Emirates and Venezuela.