BEIJING — Premier Wen Jiabao has promised China’s struggling exporters a stable exchange rate in a move that might fuel tensions with Washington over Beijing’s currency controls as the global economy weakens.

Wen’s pledge, reported by the official Xinhua News Agency and state radio, comes after the U.S. Senate approved a measure to allow higher tariffs on Chinese goods that critics say are unfairly cheap due to an artificially undervalued currency.

Beijing’s exchange rate controls are especially sensitive at a time when other nations are trying to revive growth by boosting exports and complain that a weak Chinese yuan is widening the country’s swollen trade surplus.

Wen’s pledge Friday at a trade fair in southern China came after export growth suffered an unexpectedly steep decline in September, hurt by a fall in sales to Europe amid the continent’s debt crisis.

Wen promised a “basically stable exchange rate,” Xinhua said. He pledged to maintain export-related tax rebates and other support.

U.S. manufacturers complain the yuan is undervalued by up to 40 percent, giving China’s exporters an unfair price advantage and wiping out American jobs. Beijing has allowed the yuan to gain by about 7 percent against the dollar since June 2010 in tightly controlled trading, but that is not as fast as critics want.

The measure approved Tuesday by the Senate would allow Washington to raise tariffs on goods from countries that the U.S. Treasury concludes are manipulating exchange rates for a trade advantage. The bill is not expected to become law because it lacks the support of the leadership of the lower House of Representatives, which has yet to vote on it.

China’s government reacted angrily to the measure, dismissing it as protectionism at a dangerous time for the shaky world economy and warning that trade relations would be damaged if it were allowed to become law.

China’s economy, the world’s second-largest, is relatively robust, with growth forecast by the World Bank of 9.3 percent this year. But weakening exports by Chinese manufacturers that employ millions of people could lead to layoffs and social tensions.

September’s export growth fell to 17.1 percent over a year earlier, down from August’s 24.5 percent, customs data showed Thursday.