U.S. Treasury Secretary John Snow said on Thursday it will take cooperation around the world to wind down global economic imbalances, but put special emphasis on the need for action by Asian trade giant China. "It is a matter of extreme urgency that China act immediately to increase the flexibility of its exchange rate regime before real harm is done to its own economy, to its Asian neighbors and to the global financial system," he said in prepared testimony for delivery to the Senate Banking Committee. At the outset of his testimony, Snow declared U.S. support for a strong dollar and repeated its value should be set in open markets and reflect the underlying state of the economy. He described the U.S. economy as "robust" but noted the dollar's value has been under pressure against other major currencies. Snow was before the Senate panel to discuss Treasury's semi-annual report on currency practices of key trade partners, issued last week. In the report, the Treasury pledged to push Beijing towards faster flexibility in its currency but declined to name China as a country that manipulates its currency's value for trade gain.