SHANGHAI, China - President Obama is walking a tightrope on his first trip to China, seeking to enlist help in tackling urgent global problems while weighing when and how - or if - he should raise traditional concerns about human rights.

Obama arrived in Shanghai last night in a driving rain, hustling through a phalanx of umbrella-holding dignitaries to reach his limousine.

Today, the president is holding talks with local politicians and, in one of the marquee events of his weeklong Asian trip, conducting an American-style town-hall discussion with university students.

Thirty years after the start of diplomatic relations between the United States and China, the ties are growing, but they remain mixed on virtually every front.

The two nations are partnering more than ever on battling global warming, but they still differ deeply over hard targets for reductions in the emissions of the greenhouse gases that cause it. China has supported sterner sanctions to halt North Korea's nuclear-weapons program, but it still balks at getting more aggressive about reining in Iran's uranium enrichment.

China is a huge and lucrative market for U.S. goods and services, and yet it has a giant trade surplus with the United States that, like a raft of other economic issues, is a bone of contention between the two governments. The two militaries have increased their contacts, but clashes still happen and the United States remains worried about a dramatic buildup in what is already the largest standing army in the world.

Amid all that, Obama has adopted a pragmatic approach that stresses the positive, sometimes earning him criticism for being too soft on Beijing, particularly in the area of human rights and what America regards as an undervalued Chinese currency that puts U.S. products at a disadvantage.

Obama recognizes that a rising China, as the world's third-largest economy on the way to becoming the second and the largest foreign holder of U.S. debt, has shifted the dynamic more toward one of equals.

For instance, Chinese questions about how Washington spending policies will affect the already soaring U.S. deficit and the safety of Chinese investments now must be answered by Washington.

In addition, Obama wants not to anger Beijing, but to encourage it to pair its growing economic and political clout with greater leadership in solving some of the most urgent global problems, including a sagging economy, warming planet, and the spread of dangerous weapons.

Obama has talked warmly toward China, particularly in the days leading up to his visit.

"The United States does not seek to contain China," he said in a speech from Tokyo on Saturday. "On the contrary, the rise of a strong, prosperous China can be a source of strength for the community of nations."

One test of the line Obama is walking on China will be human rights, including religious freedom in the officially atheist nation. Aides said in advance that Obama would raise several rights issues privately with Chinese leaders, including President Hu Jintao.

But it was unlikely he would repeat those messages too stridently in public, out of concern for angering his hosts. Even before arriving in China, for example, he declined to get specific about human rights with China in his Tokyo speech and eschewed the traditional presidential meeting with the Dalai Lama when the exiled Tibetan spiritual leader was in Washington in June.

Obama said he would see the Dalai Lama later, a decision welcomed by Chinese officials who pressure foreign governments not to meet with the Dalai Lama and spurn Tibetans' desires for autonomy from Chinese rule.

The White House hoped today's meeting with students would allow Obama to telegraph U.S. values - through its successes and failures - to the widest Chinese audience possible. But those hopes will have their limits in communist-ruled, tightly controlled China.

Before leaving Singapore yesterday, Obama said the United States and Russia would have a replacement treaty on reducing nuclear arms ready for approval by year's end, an announcement designed as an upbeat ending to a summit with Asia-Pacific leaders.

He also attended a second summit with leaders of the 10 countries that make up ASEAN, the Association of Southeast Asian Nations. Obama was the first U.S. president to sit in on the meetings that included a senior leader of Myanmar - part of a shift in U.S. policy away from isolating the repressive Myanmar military government.

In a bold move, he called for the release of Myanmar's dissident leader Aung San Suu Kyi, who has spent most of the last 20 years in jail or under house arrest.

White House spokesman Robert Gibbs said Obama told the gathering, including Myanmar Gen. Thein Sein, that his government must free Nobel laureate Suu Kyi and other political prisoners.

Obama's willingness to sit in the same room as a leader of the Myanmar, also known as Burma, reflected his administration's view that the United States must engage with regimes that it does not like, a sharp reversal of the Bush-era approach.

U.S. officials had pressed ASEAN leaders to include a reference to Myanmar's political prisoners in a joint statement, but that effort was unsuccessful. Instead, the statement took a softer approach, expressing support for high-level dialogue with the Myanmar government and for that nation to hold "free, fair, inclusive, and transparent" elections next year.

From Shanghai, Obama was to head to China's capital, Beijing, for the pomp and substance of a two-day state visit hosted by Hu.

Obama's China visit features the only sightseeing of his high-intensity Asian journey. He will visit the Forbidden City, home of former emperors in Beijing, and the centuries-old Great Wall outside of the city.