BEIJING — President Obama and President Hu Jintao of China met in private off

Tiananmen Square here on a frigid Tuesday morning to discuss issues like trade,

climate change and the nuclear programs of Iran and North Korea, in a session that

signaled the central role of China on the world stage.

The leaders told reporters afterward that the United States and China were in agreement

on a range of issues, but they spoke only in general terms.

At a news conference where both presidents appeared, neither took questions from

reporters, staying in line with the minutely stage-managed atmosphere of Mr. Obama’s

first visit to China. They said in separate speeches that the two nations would work

together to stabilize the teetering world economy, contain the dangers of climate change

and prevent nuclear proliferation.

The public pronouncements were full of familiar rhetoric. At the start of their first meeting,

Mr. Obama told Mr. Hu: “We believe strong dialogue is important not only for the U.S. and

China, but for the rest of the world.”

The leaders greeted each other at the door of the Great Hall of the People after Mr.

Obama’s motorcade slithered its way past thousands of onlookers crowding around

Tiananmen Square, in front of the giant portrait of Mao, to catch a glimpse of the

American president.

The leaders shook hands and walked up the red carpet, Chinese military leaders facing

them. At the conference table where the first bilateral meeting was held, Mr. Obama sat

flanked by senior cabinet members.

The meeting came the day after Mr. Obama tried to hold a frank and public discussion with

Chinese students in Shanghai. The event was called a town hall, but Mr. Obama’s

meeting with about 500 students had little in common with the sometimes raucous

exchanges that have become a fixture of American politics.

It was, instead, an example of Chinese stagecraft. Most of those who attended the event at

the Museum of Science and Technology turned out to be members of the Communist

Youth League, an official organization that grooms obedient students for future

leadership posts.

Some Chinese bloggers whom the White House had tried to invite were barred from

attending. Even then, the Chinese government took no chances, declining to broadcast

the event live to a national audience — or even mention it on the main evening newscast

of state-run China Central Television.

The scripted interaction underscored the obstacles Mr. Obama faces as he tries to

manage the American relationship with an authoritarian China, whose wealth and clout

have surged as its economy has weathered the global downturn far better than the United

States’ or Europe’s.

It remained unclear whether the United States would make progress on several issues on

this trip, including on the management of its tightly controlled currency, the renminbi, or on

how to keep Iran from developing nuclear weapons. China has rejected American

pressure to allow the renminbi to float freely and has opposed tougher sanctions on Iran.