Foreigners caught in a clash between Chinese police and nationalists in Tibet's capital told of diving behind vendors' tables and running down narrow alleys as troops opened fire without warning.

"People were falling and screaming. I saw people carrying wounded Tibetans on their backs, running into their houses and trying to find some place to hide," said Ron Schwartz, a sociology professor at the University of Newfoundland in St. Johns, Canada.He said he dashed up a street to dodge police bullets and tear gas. "It seemed like an eternity I was running up that street," he said in a telephone interview Sunday with The Associated Press.

The clash broke out Saturday in Lhasa when 30 Tibetans, identified by the official Xinhua News Agency as Buddhist monks and nuns, marched into a market with the banned Tibetan flag to commemorate the 40th anniversary of the U.N. Declaration on Human Rights. The protesters, dressed in street clothes and face masks, demanded an end to 38 years of Chinese communist rule over the Himalayan Mountain region.

China said Sunday that a Buddhist monk was killed and 13 people were wounded when police fired at demonstrators. Schwartz said the monk had been carrying Tibet's banned flag.

Police "appeared, marching in a tight formation. They fanned out in an arc, some very close to the monks," said Schwartz. He and the other foreign witnesses said the police then opened fire without warning.

The nationally televised evening news said police "were forced to fire" when "some troublemakers refused to heed a warning and threw stones and bottles at police."

"The soldiers were running after us. They came so close," said Christa Meindersma of Amsterdam, the Netherlands, who was shot in the left arm.

"They started shooting, and we started running. I ran for my life," said another witness, an English woman who spoke on condition of anonymity.

One traveler, speaking on condition of anonymity, said a Tibetan who went to a hospital to give blood for the wounded saw four bodies.

The foreigners, who spoke by telephone from their hotels, said authorities imposed tight security in Lhasa and searched foreigners' hotel rooms on Sunday.