The man destined to be China's next leader has won an extraordinary welcome across Washington on his first visit to the US.

Trading kind words of cooperation, President Barack Obama and Xi Jinping spoke directly about human rights and worsening foreign crises. "I'm sure the American people welcome you," Obama said.

Everything about the day reflected just how much China and the United States need each other, no matter what their differences, given their economic and military might and global influence.

Xi had a lengthy Oval Office audience with Obama, an elaborate reception at the State Department, full military honours at the Pentagon, a gathering with chief business executives and a dinner at Vice President Joe Biden's house.

At the centre of it was a president seeking four more years in charge and the man expected to lead China for the next decade. Xi is currently vice president and expected to succeed Hu Jintao as head of China's Communist Party late this year and become president in 2013.

Obama and Xi said they would maintain a relationship based on the traditional diplomatic speak of mutual interests and respect. They kept their focus on a diverse and cooperative agenda, although Obama did push China on human rights and the importance to recognize the "rights of all people".

In a separate setting, Xi later defended his country's rights records over the past 30 years but added: "Of course there's always room for improvement on human rights." His comments at the State Department luncheon were similar to those made by Hu during a state visit to Washington a year ago.

Outside the gates of the White House, several hundred protesters marched, waving Tibetan flags and demanding freedom for Tibet. It underscored the sensitivity of the rights issues among China's critics.

Inside the Oval Office, Obama assured Xi: "It is absolutely vital that we have a strong relationship with China." The visiting leader smiled and looked at ease in his first formal meeting with the U.S. president.

Xi said that his meetings in Washington, to be followed by stops in the Iowa heartland and then California, were aimed not just at better political ties but a deeper friendship with the American people. By the end, he may even take in a Los Angeles Lakers basketball game, said a smiling Obama, a basketball fan himself.