IEA chief criticizes 'artificial tightness' in energy markets, says some failed to help cool prices

His comments come as energy analysts assess the effectiveness of a U.S.-led pledge to release oil from strategic reserves to stymie surging fuel prices.

IEA chief criticizes 'artificial tightness' in energy markets, says some failed to help cool prices
His comments come as energy analysts assess the effectiveness of a U.S.-led pledge to release oil from strategic reserves to stymie surging fuel prices.