Welcomed with ancient pageantry, President Clinton began his journey through China Thursday, declaring that a commitment to human dignity and freedom is as "vital to the strength and success" of this nation as it is in America.

At village roundtables and at the summit, Clinton came to pursue the East-West relationship he calls crucial to peace and stability in the 21st century.He had said he would be striving to advance political and human rights, an issue rankling a Congress divided over his policy of cordial engagement and investigating his prior deals with Beijing. In a reminder of that political stress, six members of Congress, all Democrats, traveled with him. The administration said Republicans spurned the invitation.

Thus, the extravagant ceremonial welcome at the South Gate of the Old City of Xi'an opened a presidential mission disputed at home. Even the sendoff was marred by formal diplomatic protest after China revoked visas to bar three reporters for Radio Free Asia, a U.S. government broadcaster nettlesome to Beijing.

Clinton spoke first of U.S.-China accord, not discord. "We Americans admire your accomplishments, your economy, your hard work and vision, your efforts against hunger and poverty, your work with us on peace and stability in Korea and South Asia," Clinton said.

Then came the polite lecture:

"Respect for the worth, the dignity, the potential and the freedom of every citizen is a vital source of America's strength and success," he told a throng in the old city. "In this global information age, where both economic growth and equal opportunity are based on ideas, a commitment to providing all human beings the opportunity to develop their full potential is vital to the strength and success of the new China as well."

As for the critics, Clinton said "there may be those here and back in America who wonder whether closer ties and deeper friendship between China and America are good.

"Clearly, the answer is yes," he said. "We have a powerful ability to help each other grow."

Clinton delighted the crowd by opening his speech with a few words of Chinese: "Ni, hao ma?" - which means "Hello, how are you?" He closed by saying "Thank you" in Chinese.

Air Force One landed in the murky dusk of a city shrouded by chronic smog. At the formal welcoming rites, giant red-globe lanterns reflected in floodlights along a 200-yard broad red carpet that was Clinton's path to his greeting.

It was a rainbow scene of gowns, costumes, elaborate headdresses of dynasties long past, of men costumed as warriors parading to bow to the president, of dancers waving banners and scarlet globes on lofty staffs, all amid music from gongs, flutes and drums.

The pageant was styled as an "emperor's welcome" after rituals dating from the 7th century rulers of imperial China. Xi'an Mayor Feng Xichu presented Clinton the ceremonial gold key to the city.

But there was controversy at home, as a congressional committee in Washington heard testimony on alleged leaks of U.S. missile technology to China. A Beijing official defended the satellite deals involved.

The foreign ministry spokesman, Tang Guoqiang, said Thursday that cooperation on satellite launches "benefits both sides. Those who are in the mainstream of bilateral relations should have a correct view."

Tang dismissed U.S. investigations as "a wave of noise in the United States that is intended to obstruct the development of bilateral relations with the United States. We believe it by no means represents the attitude of most American people."

Clinton views his nine-day mission to China, first by an American president since George Bush in February 1989, as the right way to increase America's impact on human rights, nuclear weapons spread and for cooperation with Beijing to stabilize shaken Asian economies.

Yet even as Clinton flew to China, police arrested two dissidents in a display of Beijing's hard line against pro-democracy activists.

On Friday, Clinton goes to the village of Xiahe for what is billed as a roundtable discussion with ordinary Chinese citizens about their lives in a changing society. He'll speak in the village square. Then Clinton, his wife, Hillary, and daughter, Chelsea, are tourists for an afternoon, visiting the unearthed terra cotta warriors, pottery soldiers fashioned to guard an emperor in the afterlife.

Then to Beijing on Saturday, opening with the event that has stirred the greatest controversy at home: a formal welcoming in Tiananmen Square, scene of the democracy demonstrations bloodily repressed by Chinese troops in June 1989.

Clinton defends his visit to that symbolic site as protocol, not substance, and said he will speak America's piece for human rights and freedom. But not there; no speeches at Tiananmen.

The president said it would be wrong for him to demand that the Chinese change the way they welcome world leaders to Beijing but "equally wrong for me to go there and take no notice of the continuing difficulties with human and political rights."

He said he will do both, the latter, probably, in an address at Beijing University on Monday.

Back home, critics kept up the pressure. The House voted late Wednesday to include in a $250 billion defense spending bill a provision that would bar the Pentagon from buying any product manufactured by the Chinese government or its army.

But House Speaker Newt Gingrich, R-Ga., a tough critic of Clinton's policy, said Thursday he favors extending normal trade relations with Beijing, which Clinton is seeking.

The weekend is the actual summit with Chinese President Jiang Zemin, the joint meetings of U.S. and Chinese officials and the state banquet at the Great Hall of the People. Clinton and Jiang are to dine privately Sunday evening.