While the article helped add another 8% to oil's three-day surge - the biggest three-day jump since 1990 - by Tuesday it seemed clear there was no sign of a significant shift in Opec policy or any indication of a fresh push to shore up markets, Reuters reported.

A Gulf delegate said the Bulletin reflected genuine concern within the organisation about falling prices but it did not signal a policy shift or pending production cut.

"I see it as a message sent to the market that we are willing to talk to non-Opec, we are concerned about prices and we are not closing our eyes to what's going on," the delegate told the news wire.

Another Opec insider said: "I found it surprising," referring to the jump in prices on Monday. "The Bulletin wasn't saying anything new."

The Bulletin, a glossy magazine, is written by Opec's PR department based in Vienna and lists 12 editorial staff. It is reviewed by senior officials at the Opec secretariat before publication.

In the magazine, the following disclaimer appears under the heading "editorial policy": "The contents do not necessarily reflect the official views of Opec nor its member countries."

While the Bulletin has included similar commentaries on the market before - in April it criticised unidentified non-member countries for not cooperating in propping up prices - it does not tend to move oil prices.

Traders are wondering whether Opec and its de-facto leader Saudi Arabia will stick with the policy adopted in 2014 of defending market share, even after the slide in oil prices to their lowest in more than six years last month.

Any excitement generated on Monday appeared to be fading on Tuesday as oil prices tumbled by more than 8%, settling at $49.56 a barrel, after falling as low as $49.24.