Washington/San Francisco - Senator Hillary Clinton called Monday for President George W Bush to boycott the opening ceremonies at the Beijing Olympics in August because of China's crackdown in Tibet and other human-rights abuses.

"At this time and in light of recent events, I believe President Bush should not plan on attending the opening ceremonies in Beijing, absent major changes by the Chinese government," said Clinton, who is locked in a tight race with Barack Obama for the Democratic presidential nomination.

Clinton's statement came as protests began in San Francisco in anticipation of Wednesday's arrival of the Olympic torch, whose journey Monday through the streets of Paris was marred by clashes between protestors and French police.

Three protestors climbed San Francisco's famous Golden Gate Bridge and unfurled a Tibetan flag and banners proclaiming "One World One Dream" and "Free Tibet."

"We are part of the global independent movement for Tibet, and we are calling the world's attention to what's happening in Tibet right now," protestor Laurel Sutherlin told a local TV station as he dangled more than 50 meters above the bridge's deck.

"China is trying to take this Olympic torch around the world and use it as an opportunity to become a global player. We are looking to unmask this propaganda and let the world know there's brutal oppression happening in Tibet."

Police arrested four people on the bridge who appeared to be the support team for the cable climbers, before taking the three climbers into custody when they descended after two hours aloft.

The torch procession has been plagued by several protests, including at the initial lighting in Greece.

Clinton faulted Beijing for the violence in Tibet and for "the failure of the Chinese government to use its full leverage with Sudan to stop the genocide in Darfur." She said that the Bush administration had been "wrong to downplay human rights in its policy towards China."

Bush has said he intends to participate in the opening ceremonies but will continue to press China on its human-rights record and to open dialogue with Tibet's spiritual leader, the Dalai Lama.

"We have a great deal of concern about human rights in China, ... and we have never been afraid to express those views, either directly by the president or the president's senior advisers when they travel to China, and publicly," said Tony Fratto, a White House spokesman.

San Francisco police were readying for major protests along the only US parade route for the Olympic torch relay. The path along the waterfront is designed to minimize potential disruptions by numerous protest groups.

A declarations from the San Francisco's governing Board of Supervisors calling on the city to greet the Olympic torch with "alarm and protest."

US State Department spokesman Sean McCormack said the agency stands ready to assist San Francisco and California state authorities with any security needs.

"Clearly there's been a lot of emotion surrounding this issue worldwide. We've seen that," McCormack said.

"People have the right to freely express themselves around the world. If they have differences with the Chinese government on any variety of issues, they should have the ability to express themselves in a peaceful way."(dpa)