The United States has raised concern over a recent fall in China's yuan currency and a lack of transparency in suspected currency intervention, a senior U.S. treasury official said on Tuesday.

Chinese officials have showed their continued commitment to reforms to allow market forces to determine interest rates and the exchange rate, despite the country's slower economic growth, the official said.

"Market access and the exchange rate are top priorities for us. The challenge for China is going to be the follow through. These reforms are important to them, and important to us," U.S. Treasury Secretary Jack Lew told a briefing after meeting Chinese officials.

Lew said China needed to move to a market-based exchange rate, following a warning from the Obama administration last month that the yuan was too weak.

The yuan has fallen some 3 percent so far this year, in a move traders said was engineered by the People's Bank of China to shake the market out of the view that it was a one-way bet.

During a meeting with the U.S. treasury official, Chinese officials also expressed confidence that they would be able to achieve the government's economic growth target of around 7.5 percent this year, the U.S. official added.

Vice Finance Minister Zhu Guangyao said on Tuesday that China would not take large-scale stimulus measures to smooth short-term growth fluctuations, as the country's basic economic situation has not changed.

His comments came after official April data showed across-the-board weakness in activity, with data from output to investment and consumption all missing market expectations, sparking new calls for Beijing to ease policies to shore up growth.

"We believe that China has the policy tools to manage issues that may arise," Lew said.