Washington ? The Bush administration opened a new front Friday in its campaign to pressure China to raise the value of its currency, demanding that the International Monetary Fund crack down on countries that engage in “currency manipulation.”

The demand came in a speech by Timothy Adams, the Treasury undersecretary for international affairs, who used blistering language in criticizing the IMF for a number of shortcomings. Most significant was Adams’s allegation that the IMF has failed to enforce its own rules that bar member nations from maintaining artificially cheap currencies.

The speech did not mention China explicitly, but its primary aim was clearly to muster new force behind calls for Beijing to raise the value of the yuan.

China’s critics contend that the yuan’s exchange rate of slightly more than 8 yuan per dollar – where Beijing has held it for much of the past decade – is far out of line with market forces and gives Chinese manufacturers a big advantage against foreign firms, adding to the enormous U.S. trade deficit and China’s burgeoning trade surplus.