The Bush administration's second-ranking diplomat warned on Wednesday that a boycott of the Beijing Olympics over China's crackdown in Tibet could "inflame tensions or polarize attitudes" among 1.3 billion Chinese citizens looking with pride to the games.

Deputy Secretary of State John Negroponte also told lawmakers the United States is concerned about China's "strident rhetorical attacks" against the Dalai Lama. He said public vilification of the exiled Tibetan spiritual leader will not help ease tension in Tibet.

"If Beijing does not engage with the Dalai Lama now, it will only serve to strengthen those who advocate extreme views," he said.

Speaking at a hearing of the Senate Foreign Relations subcommittee on Asia, Negroponte said the U.S. is deeply troubled by reports of bloodshed and arrests in Tibet. While not advocating a boycott, he acknowledged calls for a boycott reflect real concerns with China's human rights record.

President Bush has said he will use his presence at the games to raise human rights issues directly with China's leaders. British Prime Minister Gordon Brown and German Chancellor Angela Merkel have said they will not attend the Olympic opening ceremonies. Senior U.S. lawmakers have urged Bush to skip the ceremonies.

Negroponte gave no indication that Bush will not attend the event. He said Bush "believes that it is important to show the Chinese people that we welcome their entrance on the international stage."

Any Olympic protest by the United States would deeply offend a proud Beijing leadership that hopes the games will show China's emergence as a new world power. It also would run the risk of hindering a host of international efforts the Bush administration needs China's help to solve, including efforts to confront Myanmar's military junta and nuclear efforts in North Korea and Iran.

China has been working hard to contain violence in Tibet ahead of the games. It sent thousands of police and army troops to the region to maintain an edgy peace, hunt down protest leaders and cordon off Buddhist monasteries whose monks led protests that began peacefully on March 10 before turning violent four days later.

Negroponte said it is a U.S. priority to establish a permanent diplomatic presence in Tibet's capital Lhasa, something members of Congress have called for.

Democratic Sen. Barbara Boxer, D-Calif., urged Bush to travel to Tibet during his trip to the Olympics, saying such a visit would be a strong symbol of support.