OPEC this afternoon agreed to raise output by two million barrels a day, at the bottom end of expectations, a deal that failed to make any immediate impact on high world oil prices.
The deal by, effective July 1st, also promises to add a further 500,000 barrels a day from August 1st.
"It's a good agreement, we will be able to test the impact of the policy on the oil market before we meet again in July," said Qatar Oil Minister Mr Abdullah al-Attiyah.
"We are very concerned about high oil prices and their impact on the world economy," said OPEC President Mr Purnomo Yusgiantoro.
The group meets again on July 21st to review policy.
The deal lifting formal group output limits by eight per cent to 25.5 million barrels daily will be a disappointment for those expecting OPEC to deliver more.
Oil prices rose. U.S. crude by 15.30 (Irish time) was up 26 cents at $40.25 a barrel.
The official details are unlikely to make a lot of difference to actual supplies from the cartel that controls more than half the world's oil exports.
That's because group output already is at or above official new quota limits.
Regardless of official policy, Saudi and the United Arab Emirates confirmed to reporters they would deliver about a million barrels daily of real extra oil in June.
Saudi Arabian Oil Minister Mr Ali al-Naimi confirmed he was pumping up to 9.1 million, an addition of about 700,000 bpd. UAE is adding 400,000 bpd.
Others in OPEC are at, or close to, full capacity. Delegates said the formal pact was a compromise between Saudi and countries like Iran and Venezuela which feared a price collapse.
Riyadh had pressed for 2.5 million barrels daily immediately, worrying that a slowdown in economic growth could hit fuel demand.
Oil prices have been around the $40 mark for the past three weeks, fuelled by strong world economic growth and worries about supply security in the Middle East.
Concerns about political instability in Saudi Arabia were inflamed on Saturday by a deadly attack by Islamic militants in the Saudi oil city Khobar.