BEIJING (AP) -- U.S. Treasury Secretary Henry Paulson says Chinese leaders assured him they are committed to currency flexibility and more financial reforms, but Beijing offered no specific changes that could help assuage U.S. congressional ire over China's huge trade surplus.

"I heard from everyone, right up to the top, they are committed to currency flexibility, to currency reform," Paulson said Wednesday as he wrapped up two days of talks.

Officials said they plan to lift a 10-month-old moratorium on new Chinese-foreign joint-venture securities brokerages in early autumn, instead of December as originally planned, Paulson said.

The secretary, who is leading a "strategic economic dialogue" with China, is trying to avert drastic action by congressional critics who are pressing for sanctions over Beijing's currency controls. They say China's currency, the yuan, is kept undervalued, giving its exporters an unfair advantage and adding to its multibillion-dollar trade surplus.

Also Wednesday, congressional efforts to pressure Beijing took a step forward when a Senate committee approved a bill that would require the administration to pursue currency manipulation cases before the International Monetary Fund. One of its sponsors said it would remove what he termed a "loophole" that has allowed the U.S. Treasury to avoid citing China as a currency manipulator.

Analysts had not anticipated any concessions from Beijing during Paulson's visit. But he was expected to use the trip to try to persuade Congress that his dialogue is making progress.

Paulson said he discussed that process in meetings with Chinese President Hu Jintao and Vice Premier Wu Yi, Beijing's top envoy to the dialogue.

Paulson said he made the case that China would benefit from a faster appreciation of the yuan. But he gave no indication that Chinese leaders promised a quicker rise or any other specific changes.

Paulson suggested the Chinese might be growing impatient with the wide range of issues raised by Washington.

"They're too polite to say they're frustrated, but I do believe they are asking themselves, will they ever able to satisfy us," he said.

Paulson, speaking ahead of the Senate vote, said he shared American lawmakers' frustration at the slow pace of reform and expressed confidence they would understand he is making progress.

However, he acknowledged: "I've got more work to do with Congress."

The secretary also met with China's central bank governor, finance minister and banking and securities regulators.

Paulson has been granted unusually wide access to top Chinese officials in a sign of the urgency Beijing places on preserving trading relations with the United States.

The United States reported a trade deficit of US$235 billion with China last year.

Chinese leaders say they plan eventually to let the yuan trade freely on world markets. But they say acting too abruptly will hurt China's frail banks and cause financial turmoil.

China revalued the yuan by 2.1 percent against the dollar in July 2005 and has allowed it to rise by about 7.2 percent since then. The rate of increase has speeded up in recent months, but analysts expect Beijing to restrain the yuan's rise to about 5 percent annually over the next few years -- far less than critics want.

Paulson has pleaded with Congress for time to let the dialogue work. But China's supercharged growth is fueling arguments that it can afford to move faster.

China's economy expanded 11.9 percent last quarter -- the fastest quarterly growth in 12 years -- and the trade surplus jumped by 85 percent in June to $26.9 billion.