BEIJING -- Seeking help with an array of global troubles, President Barack Obama said Tuesday that his closely watched talks with his Chinese counterpart are vital not just for their nations but the world.

Obama and Chinese President Hu Jintao sent cooperative signals before they began closed-door meetings that were likely to touch on challenges ranging from nuclear proliferation, hurting economies, climate change and human rights.

The pair sought to strike a balance between trading partners and competitors during Obama's first trip to China amid a tour of Asia.

"We believe strong dialogue is important not only for the U.S and China, but for the rest of the world," Obama said, flanked by his national security team as the session began with great ceremony.

Hu reciprocated with kind words in public: "I look forward to having an in-depth relationship."
After those brief comments to reporters, the two presidents opened more than two hours of private talks at the Great Hall of the People, located on the edge of Tiananmen Square.

The buildup to the meetings in China brought a cautious balancing from the first-term U.S. leader.
A day before, Obama prodded China about Internet controls and free speech during a forum with students in Shanghai. His message was not widely heard in the country; his words were drastically limited online and shown on just one regional television channel.

He also suggested that China, now a giant in economic impact as well as territory, must take a bigger role on the world stage -- part of "burden of leadership" it shares with the United States.
"I will tell you, other countries around the world will be waiting for us," Obama said in an American-style town-hall discussion with Chinese university students in Shanghai, where he spent a day before flying to China's capital for a state visit with President Hu.

Eager to achieve a successful summit, the two leaders were likely to avoid public spats on economic issues. With America's budget deficit soaring to a yearly record of $1.42 trillion, China is the No. 1 lender to Washington and has expressed concern that the falling price of the dollar threatens the value of its U.S. holdings.

In the U.S., American manufacturers blame China's own low currency value for contributing to the loss of 5.6 million manufacturing jobs over the past decade. During that time, America's trade gap with China has soared.

Obama's town hall meeting in Shanghai on Monday showed how difficult it is for the governments to work together. The U.S. initially requested a larger venue and a live broadcast on a major network. In the end, Chinese officials put the event on the eastern fringes of the city. Only local Shanghai TV carried it live, though it was streamed on two popular Internet portals and on the White House's Web site, which is not censored.

In brief remarks before the initial talks, Hu noted Obama's Shanghai meeting with students, calling the session "quite lively."

Obama smiled broadly throughout the welcoming remarks late Monday, then told Hu that "the world recognizes the importance of the U.S.-Chinese relationship" in tackling global problems.
The two met again -- more formally -- on Tuesday, complete with the military pomp of a welcome ceremony at the Great Hall of the People and a joint appearance before reporters. 

With sightseeing in Beijing's Forbidden City sandwiched in between, the two leaders' day was to end at a lavish state dinner in Obama's honor.

"Mr. President, let me say on behalf of the American people how very grateful we are for your hospitality," Obama said at the top of his first meeting Tuesday.

Obama was spending Wednesday in Beijing as well before completing his weeklong Asia travels in South Korea.

Topmost on Obama's ambitious agenda with Hu is the so-far elusive search for global agreement on a new climate change pact, stymied by disagreement between rich nations like the U.S. and developing nations such as China. Wealthier countries want legally binding greenhouse-gas reduction targets for themselves as well as for energy-guzzling developing nations such as China, India and Brazil. Those poorer nations say they will set only nonbinding goals and they demand assistance to make the transition to harder targets.

Amid those differences, Obama and Hu are expected to announce new cooperation on a related but easier front: clean-energy projects. With China and the U.S. the world's two largest emitters of heat-trapping gases, Obama warned that "unless both of our countries are willing to take critical steps in dealing with this issue, we will not be able to resolve it."

Another key area for Obama is securing stronger Chinese backing for halting the nuclear weapons ambitions of Iran and North Korea.

Beijing has supported sterner sanctions against Pyongyang for its continued nuclear weapons program. And, as North Korea's last major ally and a key supplier of food and energy aid, China is a partner with key leverage in six-nation talks with the North over the issue. 

But on Iran, where China has significant economic ties, Beijing has appeared less willing to endorse a tougher approach to restrict Tehran's uranium enrichment and suspected pursuit of atomic bombs.