"Aramco had communicated with us about additional supplies but we have not explored that option. We did not ask for more because we do not need any more Arab Heavy barrels," Reuters quoted one European customer, who asked not to be named. "There will be no change in our allocation from March."

The customer, a regular buyer of Libyan oil that also has a term contract with Saudi Arabia, received notice of its crude oil supply allocation from Aramco ahead of others.

Libya normally produces about 1.6 million barrels per day of light, low-sulfur crude oil. But the unrest in the North African country has resulted in an estimated loss of 1 million bpd of output.

Saudi Arabia, the world's top oil exporter, said late in February it would fill in any supply shortage caused by the political unrest in Libya, Reuters said.

Three other customers said they expected to receive a notice from Saudi Aramco about their April allocations next week, and that they had asked for the same volume as March.

One of them said many European refineries have been forced to cut oil product output due to weak refining margins rather than buy more oil when North Sea benchmark Brent crude has remained high, near $115 a barrel, Reuters said.

Minister of Petroleum and Mineral Resources Ali Al-Naimi told the state news agency SPA that the Kingdom had access to a large number of oil storage facilities around the world which would give it flexibility to meet any additional demand.

Saudi Arabia has increased supplies to a storage facility in Rotterdam and Sidi Kerir, he said.

Meanwhile, reacting harshly to the recent Goldman Sachs report accusing Saudi Arabia of misleading the world about its oil production capacity, John Sfakianakis, chief economist at Banque Saudi Fransi, Riyadh, told Arab News: "Saudi Arabia is aware of its systemic role in global oil markets and is not the business of misleading. In fact, its mission is to provide necessary supply, maintaining extra capacity above all, as per market dynamics and often speculators are in the business of taking positions in the paper oil market just as they produce research notes."

"In today's oil market, exaggeration and speculation have fueled an unfounded spike in oil prices. Saudi Arabia's is not in the business of misinforming oil markets as the danger of losing one’s credibility is a far greater disincentive than simply making short-term supply inroads. Saudi Arabia has always called for greater transparency in oil markets, and now is the time for greater oversight of market punters through proper legislation," Sfakianakis added.

However, Jarmo T. Kotilaine, chief economist at the National Commercial Bank, said assessing the veracity of these claims is naturally impossible with the currently available information, although some of the suggestions made were provoking. But the broader point of importance here was that the oil market was once again beginning to run into supply constraints at a time when the global economy is still only emerging from a major downturn. Now of course it was doing so in an environment characterized by an additional cluster of major risks: The situation in Libya, concerns over the impending completion of the US Federal Reserve's QE2 program, and significant structural pressures in many commodities. It was this unusual constellation of risks that made markets sensitive to speculation about supply constraints, something that would likely remain a recurrent phenomenon quite apart from the Goldman report.

"The ultimate worry is that the global economy is moving toward a 1970s-'80s-style stagflation scenario and there are few easy solutions to this challenge in the near term. The implication for global growth are negative — whether as a result of stagflation or as a consequence of the kinds of painful policy shifts that would be needed to put global growth on a sound footing again," Kotilaine said.