The average crude oil prices of the Organization of Petroleum Exporting Countries (OPEC) dipped slightly on Friday, after three consecutive days of hike, the cartel's secretariat reported on Monday.

The prices edged down to 67.02 U.S. dollars per barrel on Friday, a fall of 0.25 dollars from the precious day, the report said.

The International Energy Agency has revised its forecast for the world oil demand in 2006, lowering it by 0.2 million barrels as a result of record-high fuel prices.

OPEC officials believed that the high oil prices would restrain the crude oil demand, and slow the global economic growth.

"When prices are high, people check their pockets," said Ali al-Naimi, the oil minister for Saudi Arabia, on Monday at the Energy Ministers Conference of Arab Countries in Amman, Jordan.

But oil market analysts were still worried about the crude oil supply. They warned that the drop of the oil prices would be just slight, and then go even higher, citing the decline of the oil output in Nigeria which had caused the decrease of crude oil supply from OPEC, and the perspective of the Iran's nuclear issue which was unpredictable.

They said that once Iran's nuclear problem is solved by diplomatic measures, the international oil prices will drop gradually.

"The oil prices would cut 40 percent to 50 percent within the following 18 months, if the tension between the West and Iran could be mitigated," Johannes Benigni, managing director of PVM Oil Associates in Vienna, told a local newspaper.

With the backing of the United States, the European Union is set to refer a new plan to encourage Iran to curb its nuclear program.

Source: Xinhua