US lawmakers agitating for trade sanctions against China said they would visit the country this week to give Beijing a last chance to stage decisive reform of its currency regime.
Democratic Senator Chuck Schumer and his Republican colleague Lindsey Graham said China must revalue the yuan now if it wants to avert a vote by March 31 that could impose a hefty tariff of 27.5 percent on its US-bound exports.
Their week-long trip starting Sunday, which the senators said has the blessing of the White House, comes as Chinese President Hu Jintao prepares to visit Washington next month.
Schumer said the trip to Beijing, Shanghai and Hong Kong, which is being joined by Republican Senator Tom Coburn, would encompass meetings at the "highest levels" of the Chinese government.
"The need to go to China and really find what's going on in the advent of the deadline for our legislation and President Hu's upcoming visit is essential," the New York senator told a news conference.
"We truly hope that we're given some reason for optimism that China will revalue its currency and play by the rules on our visit," he said.
The senators argued that the yuan is undervalued by as much as 40 percent against the dollar, dealing a crippling blow to US companies trying to compete against Chinese rivals.
The currency exchange rate, critics contend, helped to drive up China's trade surplus with the United States to 202 billion dollars in 2005, the largest bilateral trade gap in history.
However, Chinese Premier Wen Jiabao appeared to rule out any more reforms to the yuan exchange rate when he promised Tuesday "no more surprises" on the currency.
Since July, the yuan has been linked to a basket of currencies rather than pegged tightly to the dollar. But it has only risen about three percent against the greenback since then.
"For us to put the vote off ... I have to be convinced that it's more than a fig leaf, that it's real reform," said Graham, who represents South Carolina.
"The Chinese government needs to understand that from all corners of this country, the frustration with their trading practices is at a boiling point," he said.
"This is deadly serious. We know the consequences of our bill are deadly serious. I'm not doing this lightly. So I'm going with the idea of communicating the stress points and see what kind of action will follow."
The senators' mission comes as anger mounts in all branches of the US government over China's exchange rate, its perceived inaction against rampant copyright theft and its unwillingness to grant more access to US companies.
On Tuesday, Commerce Secretary Carlos Gutierrez departed from the administration's softly-softly script on China to issue some of its bluntest words yet.
"Without concrete results, the administration, and the American people, may be forced to reassess our bilateral economic relationship," he said.
"And without results, I'm afraid Congress may go down a path that none of us want."
The Schumer-Graham tariffs legislation won 67 votes in the 100-seat Senate last year in a procedural motion, enough to overcome any presidential veto if that level of support is sustained in a full vote.
Schumer said he would "bet money" that it would command even more backing now should a vote be called by the senators' target date of March 31, and at least as much in the House of Representatives.
"We've been very patient," Schumer said, noting that a vote on the tariffs legislation has been repeatedly postponed to give Beijing more time to revalue.
"Our inclination is we don't want to delay it again. But we thought in all fairness, we should go and find out what the Chinese have to say."