Sadad al-Husseini, a geologist and former head of exploration at the Saudi Arabian oil monopoly Aramco, has warned that his country may have far less oil than experts previously thought.

Also, the U.S. consul in Saudi Arabia has warned America that it should take that warning seriously. Those warnings were revealed when secret cables were released by WikiLeaks to the London Guardian newspaper.

"According to al-Husseini, the crux of the issue is twofold," the text of one cable read. "First, it is possible that Saudi reserves are not as bountiful as sometimes described, and the timeline for their production not as unrestrained as Aramco and energy optimists would like to portray."

"In a presentation, Abdallah al-Saif, current Aramco senior vice president for exploration, reported that Aramco has 716 billion barrels of total reserves, of which 51% are recoverable, and that in 20 years Aramco will have 900 billion barrels of reserves," the text of another cable advised.

Other experts agree with al-Husseini's warning.

The revelations came as the price of oil has risen in recent weeks to more than $100 a barrel due to global demand and the rising tensions in Egypt.

Some said a global oil shortage could be worse than the recent world economic credit crunch.