Oil engineers continue to seek further exploration as --

 The head of Opec raised the stakes in the battle over high oil prices yesterday when he dismissed a call from the US energy secretary for the producers' group to pump more crude into the market.

Abdalla Salem El-Badri, secretary general of the Organistation of Petroleum Exporting Countries, rejected claims that a worldwide crude shortage was behind the rise in price to nearly $100 dollars a barrel, and added that the US itself could do more to ease its problems.

Samuel Bodman, the US energy secretary, had stepped up the pressure on Opec on Tuesday evening, saying that the group's meeting in Riyadh this week should decide to raise production to help reduce the high oil prices that are threatening to stall economic growth.

Whilst China is taking further steps to alleviate the impact of higher fuel costs