THE Chinese authorities had been fearing trouble, but nothing on this scale. An orgy of anti-Chinese rioting convulsed the Tibetan capital, Lhasa, on Friday March 14th, leaving security forces uncertain how to respond. For many hours mobs controlled the streets, burning and looting as they pleased.

The approach of Beijing's Olympic games in August is seen by many of Lhasa's residents as an opportunity to put their contempt for Chinese rule on display to the outside world. China's desire to ensure the games are not marred by calls for boycotts is tying its hands as it considers how to respond.

Your correspondent, the only foreign journalist with official permission to be in Lhasa when the violence erupted, saw crowds hurling chunks of concrete at the numerous small shops run by ethnic Chinese lining the streets of the city's old Tibetan quarter. They threw them too at those Chinese caught on the streets—a boy on a bicycle, taxis (whose drivers are often Chinese) and even a bus. Most Chinese fled the area as quickly as they could, leaving their shops shuttered.

The mobs, ranging from small groups of youths (some armed with traditional Tibetan swords) to crowds of many dozens, including women and children, rampaged through the narrow alleys of the Tibetan quarter. They battered the shutters of shops, broke in and seized whatever they could, from hunks of meat to gas canisters and clothing. Some goods they carried away—little children could be seen looting a toyshop—but most they heaped in the streets and set alight.

Within a couple of hours, fires were blazing in the streets across much of the city. Some buildings caught fire too. A pall of smoke blanketed Lhasa, obscuring the ancient Potala—the city's most famous monument, which covers a hillside overlooking the city. It is the traditional winter palace of the Dalai Lama, Tibet's spiritual leader, who fled into exile in India after an abortive uprising in 1959. Some of the demonstrators shouted slogans like “long live Tibet” and “long live the Dalai Lama”. One group trampled on a Chinese flag in the middle of a main road.

The rioting seemed primarily an eruption of ethnic hatred. Immigrants have been flocking into Lhasa in recent years from the rest of China and now run many of its shops, small businesses and tourist facilities. Tourism is the mainstay of Lhasa's economy and has been booming in recent years, not least thanks to Tibet's first railway link with the rest of China, opened two years ago. The visitors are mainly Chinese.

There is big resentment too over sharp increases in the prices of food and consumer goods from the rest of China. Many residents of Lhasa, suspicious of the new train service, which they felt might encourage immigration, had been comforted by what they say were official statements saying the rail link would help bring prices down. But they have kept on rising, as they have in other parts of the country.

Residents had mixed feelings about the violence. Some celebrated by throwing rolls of lavatory paper over wires across the streets, filling them with streamers intended to resemble traditional Tibet scarves. Others appeared aghast at the violence. As your correspondent spoke to a monk in the backroom of a monastery, a teenage boy rushed in and prostrated himself before him. He was a member of China's ethnic-Han majority, terrified of the mobs outside. The monk helped him to hide.

The violence was fuelled by rumours of killings, beatings and detention of Buddhist monks by security forces in Lhasa this week. Access to the city's big three monasteries has been blocked by police since the beginning of the week when hundreds of monks staged protests coinciding with the March 10th anniversary of the 1959 revolt. Dozens of them, residents believe, have been arrested. On Friday morning, rumours spread that monks had been shot dead outside the Jokhang temple, the holiest shrine of Tibetan Buddhism in the heart of the Tibetan quarter. A couple of monks outside another temple were said to have been beaten by police.

A handful of riot police with shields and helmets (but no guns visible) patrolled in front of the Jokhang as the riots continued around them, while others stood in lines at the perimeter of the riot-torn area. But for many hours they made no attempt to intervene. After nightfall, fire engines supported by two armoured personnel carriers, moved down the streets putting out the blazes. But the police carrying automatic rifles atop the armoured vehicles did not attempt to deploy on the streets. The occasional bang was heard, but it was difficult to tell whether it was shooting or explosions in the fires.

During the evening, Lhasa television broadcast over and over again, alternately in Tibetan and Chinese, a government statement accusing the “Dalai Lama clique” of being behind the violence by a “small number” of rioters. It called on city residents to support the authorities' efforts to restore control.

But ensuring stability in Lhasa in the coming months will be an enormous challenge for China as it prepares for the Olympics. Many residents expect a massive deployment of security forces over the weekend and possibly a reintroduction of martial-law type restrictions, as in 1989 during the last serious outbreak of unrest in the city (some say the latest protests have been the biggest since 1959). But officials in Lhasa had been preparing to host growing numbers of foreign tourists and Olympic visitors this year. A long-term visible deployment of troops would be, to say the least, a big embarrassment for the Communist Party.