At a regional conference in Singapore, Mr. Obama announced a setback on another top foreign policy priority, climate change, acknowledging that comprehensive agreement to fight global warming was no longer within reach this year.

Image President Obama signed a guest book during his tour of the Forbidden City in Beijing on Tuesday. He has taken a conciliatory tone on his first visit to China. Credit... Stephen Crowley/The New York Times

Past American presidents have usually insisted in advance on some concrete achievements from their trips overseas. President Bush received vigorous endorsements of his top foreign policy priority, the global war on terrorism, during his visits to Beijing, and President Bill Clinton guided China toward joining the World Trade Organization after prolonged negotiations. When either of those presidents visited the country, China often made a modest concession on human rights as well.

This time, Mr. Hu declined to follow the lead of President Dmitri A. Medvedev of Russia, who, after months of massaging by the Obama administration, now says that he is open to tougher sanctions against Iran if negotiations fail to curb Iran’s nuclear program. The administration needs China’s support if tougher sanctions are to be approved by the United Nations Security Council. But during the joint appearance in Beijing on Tuesday, Mr. Hu made no mention of sanctions.

Rather, he said, it was “very important” to “appropriately resolve the Iranian nuclear regime through dialogue and negotiations.” And then, as if to drive home that point, Mr. Hu added, “During the talks, I underlined to President Obama that given our differences in national conditions, it is only normal that our two sides may disagree on some issues.”

White House officials acknowledged that they did not get what they wanted from Mr. Hu on Iran but said that Mr. Obama’s method would yield more in the long term. “We’re not looking for them to lead or change course, we’re looking for them to not be obstructionist,” one administration official said.

In a meeting in Beijing with a senior Chinese official on Wednesday morning, Secretary of State Hillary Rodham Clinton again pressed China on Iran. She told the official, Dai Bingguo, that even if China had not decided what sanctions on Iran it would accept, “you need to send a signal,” said a senior American official, who spoke on condition of anonymity so he could describe the exchange.