The Organization of Petroleum Exporting Countries (OPEC)'s weekly average crude oil prices dropped to 63.71 U.S. dollars per barrel last week, a fall of 2.23 dollars from the previous week, the cartel's secretariat said on Monday.

After four consecutive days of drop, OPEC average oil prices fell down from 67.02 dollars per barrel on May 12 to 62.95 dollars per barrel on May 18.

The drop, the first time that the OPEC oil prices have edged under 63 dollars per barrel since April 11, was not only due to the high oil prices, which have contributed to a slowing of incremental oil demand, but also due to the mitigation of the tension in Iran's nuclear issue, said the oil marketing analysts in Vienna.

"Though the world oil market is well supplied," OPEC would not cut it's current output in the coming Ministers Meeting in Caracas, capital of Venezuela, on June 1, said an Iranian official last Friday.

But "Iran's nuclear issue is still the biggest potential factor, which could curb the oil prices to keep dropping," warned analysts.

The demand for OPEC crude in 2006 is expected to average 28.6 million barrels per day, representing an upward revision of 0.1 million barrels per day versus the previous month.

Source: Xinhua