OPEC is not taking any concerted action to bring oil prices below the 50 usd per barrel mark, despite the assurances of oil-producing countries that they are doing whatever they can to stabilise the market, the Centre for Global Energy Studies said in its monthly report. The CGES said Saudi Arabia -- the only OPEC member capable of influencing the market -- is showing reticence in raising its output beyond the volumes allocated to its customers, despite pressure from US President George W Bush.