The weekly average oil prices of the Organization of Petroleum Exporting Countries (OPEC) dropped to USD $109.73 per barrel last week, the Vienna-based cartel said.

The prices have dropped for six consecutive trading weeks by $28.58 after it topped $138.31 in the first week of July.

OPEC said in its monthly report Friday that the eased geopolitical tensions and concerns over slower demand growth amid weak economic signs were the main cause for the steep fall.

Other factors included a steep drop in oil demand in countries of the Organization for Economic Cooperation and Development, the United States in particular, as well as a rebound of the U.S. dollar, the cartel said.

Iran’s OPEC governor Mohammad Ali Khatibi said Saturday that the oil market is oversupplied by at least 1 million barrels a day, so the group was considering reducing its output or keeping it unchanged if demand continues to fall.

Experts, however, have again emphasized the potential risks of geopolitical crises such as Iran’s nuclear issue and the armed conflicts in Georgia’s breakaway region of South Ossetia, adding that the upcoming OPEC meeting in September would lead the oil prices to a clear direction.

(Rigzone & Xinhua)