BEIJING, MARCH 17: Vowing a harsh crackdown, Chinese police conducted house-to-house searches in central Lhasa today and rounded up hundreds of Tibetans suspected of participating in a deadly outburst of anti-Chinese violence, exile groups and residents reported.

(Agency reports, quoting activist groups, said at least eight people were killed when police opened fire on a rally led by monks in southwest China amid a wave of anti-Chinese protests outside Tibet. The demonstrations, which have seen attacks on government buildings and police stations, occurred in areas with large ethnic-Tibetan populations. China has prohibited entry of foreigners to Tibet and asked tourists to leave. The regional government of Tibet has suspended handling the application of foreigners for “safety concerns,” a local official said.)

The large-scale arrests and official promises of tough reprisals suggested the Chinese government has decided to move decisively to crush the protests despite calls for restraint from abroad and warnings that heavy-handed repression could taint next summer’s Olympic Games in Beijing.

The Tibetan regional governor, Champa Phuntsok, said detainees who show remorse and inform on others who were part of the week-long unrest would be rewarded with better treatment. But Buddhist monks and other Tibetans who participated in Friday’s torching of Chinese-owned shops and widespread attacks on Han Chinese businessmen would be “dealt with harshly,” he told a news conference in Beijing.

In a widely broadcast announcement, the government had given rioters until midnight Monday to turn themselves in, after which they were threatened with arrest. But Urgen Tenzin, executive director of the India-based Tibetan Center for Human Rights and Democracy, said he was told by telephone that about 600 Tibetans had been arrested before nightfall by a police sweep that lasted most of the day.

One Han Chinese resident contacted by telephone said a squad of policemen had knocked on the door of his home in Lhasa and demanded to see national identity cards and residence permits for all those inside. A bank officer said police entered his city-center branch and obliged employees one by one to show their national identity cards and respond to questions about their residence and activities.

“We must give them tit for tat and firmly counterattack,” said an editorial in the Communist Party’s official newspaper in Lhasa, the Tibet Daily, in an indication of the government’s determination to crack down hard.

“Ensuring the social stability of the Tibet Autonomous Region is the number one political mission,” the paper said. “It is the priority. We have to take decisive and powerful measures to firmly beat down the enemy’s arrogance and never withdraw our troops without victory... We have to severely punish the criminals who are still beating, robbing and burning, arresting them rapidly and with absolutely no mercy.”