VIENNA, Jan. 15 (Xinhua) -- The Organization of Petroleum Exporting Countries (OPEC)'s weekly average crude oil prices dropped sharply by 3.72 U.S. dollars to 50.27 dollars per barrel last week, the cartel's secretariat said on Monday.

    Although OPEC slashed its output by 1.2 million barrels per day (bpd) from Nov. 1, 2006, and agreed on a further output cut from Feb. 1, the daily oil prices kept declining last week, from 51.86 dollars to 48.65 dollars, marking the lowest point in the last 19 months.

    Marketing analysts believed that the historically mild winter temperatures both in the United States and Europe caused the drop in the heating oil demand and led to a build-up in energy inventories.

    Some meteorologists even expected the situation to continue since 2007 was projected to be the hottest year on record. Therefore, investors and speculators were betting prices would drop further.

    Over the past two weeks, OPEC oil prices have declined surprisingly by more than 7 dollars per barrel, which also caused OPEC's jitters.

    The cartel members Iran and Venezuela called on OPEC on Saturday to make further production cuts immediately if necessary.

    However, due to a poor level of compliance among the cartel members, so far it was still uncertain whether OPEC would hold an emergency meeting to prevent the prices from falling further.