UPDATE 2-Tension high ahead of San Francisco torch run

(Updates with crowds gathering)

By Adam Tanner

SAN FRANCISCO, April 9 (Reuters) - Hundreds of security officers deployed across San Francisco on Wednesday ahead of expected large protests against China policies as the Olympic torch makes its only relay in the United States.

Hours before the 1 p.m. EDT (1700 GMT) scheduled start, hundreds of pro-China spectators had already gathered at the start of the route, many flying the five-star Chinese flag whose largest star represents the Communist Party.

A fifth of San Francisco's population is of Chinese origin, and many are proud their ancestral home is hosting the global sporting event and resentful of the protests

The torch relays have became a magnet for demonstrators, many of whom are not of Chinese descent, protesting China policies from its crackdown in Tibet to its human rights record.

"A bunch of white people getting yelled at by Chinese people," is how publicist Candace Locklear described tensions as crowds with different viewpoints gathered on Wednesday morning.

Chaotic protests in London and Paris over the last week -- efforts that succeeded even in extinguishing the flame for brief periods -- have put San Francisco officials on edge in the West Coast city famous for its demonstrations.

Some 700 security officers including agents from the FBI deployed and airspace restrictions were in place overhead. Barricades were set up outside the Chinese consulate and officials planned to halt the city's famed cable cars for much of the day.