BEIJING — President Barack Obama and Chinese President Hu Jintao emerged from hours of intense talks today determined to marshal their combined clout on crucial issues, but still divided over economic, security and human rights issues that have long bedeviled the two powers.

"The relationship between our two nations goes far beyond any single issue," Obama said in a joint appearance with Hu that followed about 21/2 hours of private conversations.

Both leaders spoke in bold terms of the growing relationship between the countries and emphasized cooperation on the economy, climate change, energy and the nuclear threats of Iran and North Korea.

But in those areas and others, there remained differences that underscored that tensions would hardly be erased in Obama's first, high-profile visit to China. Obama spoke at length about the nations' joint interests and said, "I do not believe that one country's success must come at the expense of another."

Obama and Hu said they agreed on restarting the collapsed six-nation effort to rid North Korea of its nuclear programs. The Chinese said the effort was essential to "peace and stability in northeast Asia."

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 major leverage in six-nation talks with the North over the issue.

On Iran, where the U.S. needs China's clout to help pressure the nation to give up any of its own nuclear weapons positions, Obama spoke with sterner language than Hu.

"Iran has an opportunity to present and demonstrate its peaceful intentions, but if it fails to take this opportunity, there will be consequences," the U.S. president said. Hu made no mention of consequences, saying the Iran conflict is important to resolve through negotiations.

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

In a minor step forward, Obama announced that the governments will reconvene their on-again, off-again human rights dialogue early next year. Previous rounds have fallen casualty to disputes over arms sales to Taiwan and other issues.

Hu expressed disappointment with the Obama administration over its decision to impose punitive tariffs and duties on imports of Chinese tires and steel pipes. "Our two countries need to oppose and reject protectionism in all its manifestations in an even stronger stand," Hu said.