KATHMANDU, Nepal — The Dalai Lama accused China of “cultural genocide” yesterday as violent clashes over Beijing’s rule in Tibet spread to neighboring provinces.

Demonstrations broke out in Sichuan, Qinghai, and Gansu provinces, prompting the authorities to mobilize security forces across a broad expanse of western China.

In the Tibetan capital, Lhasa, police searched buildings as a midnight deadline loomed for people who took part in last week’s violent anti-Chinese uprising to surrender or face severe punishment.

Speaking from his seat of exile in India, Tibet’s spiritual leader, the Dalai Lama, called for an international investigation into China’s crackdown in Lhasa, which is believed to have claimed 80 lives.

“Whether intentionally or unintentionally, some kind of cultural genocide is taking place,” the Dalai Lama said, referring in part to ethnic Chinese immigration and restrictions on Buddhist worship that have generated deep resentment among Tibetans. An “ancient nation with ancient cultural heritage is actually dying,” he said.

Tensions boiled over in Aba, Sichuan province, when armed police tried to stop a crowd of Tibetan monks from protesting.

An eyewitness reported that a policeman had been killed and three or four police vans set on fire.

Eight bodies were delivered to a nearby monastery and up to 30 protesters were shot, according to two activist groups, the Tibetan Centre for Human Rights and Democracy and the Free Tibet Campaign.

Though many demonstrations were small in scale, the widening protests have meant that extra police have had to be drafted in from other towns to help in the efforts to quell them. The demonstrations follow nearly a week of protests in Lhasa that escalated into violence last Friday, with Tibetans attacking ethnic Chinese and torching their shops in the longest and fiercest challenge to Chinese rule for 20 years.

Gunfire continued to be heard throughout the city yesterday and armed police went from house to house searching for and arresting protesters.

Few people dared to step outside their homes. “Every 20 or 30 minutes one hears a shot, or two or three together. At one point I heard a brief burst of automatic fire nearby,” a Westerner staying at a hotel in the old quarter told the Daily Telegraph.

The area has now been flooded with soldiers, with reports that 200 military vehicles, each carrying between 40 and 60 soldiers, arrived yesterday.

Loudspeakers broadcast messages urging residents to “Discern between enemies and friends, maintain order” and to “Have a clear stand to oppose violence, maintain stability.”

Tibet enjoyed a degree of autonomy for decades before communist troops entered in 1950. The current unrest began on March 10, the anniversary of a 1959 uprising against Chinese rule.

The Tibetan kingdoms of the past spread far beyond what China refers to as modern Tibet, and many inhabitants of neighboring regions still revere the Dalai Lama.

Inspired by the goings-on in Lhasa, monks and inhabitants of the town of Xiahe staged two days of protests, one peaceful, in which they raised Tibetan national flags, and the other violent, in which government offices were smashed and the crowd of more than 1,000 were tear-gassed by the police.

Many Tibetan residents spent the weekend on the rooftops of their buildings, as speculation spread of revenge attacks by ethnic Chinese.

To China’s embarrassment, the protests come two weeks before celebrations for the Beijing Olympics start with the torch relay, which will pass through Tibet.

Beijing had hoped the games would boost its image abroad, but the event has attracted growing scrutiny of its human rights record.