BEIJING – Chinese police tore up a protester’s poster and detained at least two people on Beijing’s Tiananmen Square yesterday as the country marked 17 years since local troops crushed a pro-democracy demonstration in the public space.

An elderly woman tried to pull out a poster with apparently political material written on it, but police ripped it up and then took her away in a van.

A farmer tried to stage a protest apparently unrelated to the 1989 crackdown, but he also was taken away in a van.

After dawn, a group of tourists tried to open a banner while posing for a photo, catching the attention of police, who quickly forced them to put the non-political material away. They were not detained.

Discussion of the crackdown is still taboo in China outside the semi-autonomous regions of Hong Kong and Macau. Chinese television news and major newspapers did not mention the anniversary.

In Hong Kong, several hundred people holding candles gathered at Victoria Park, creating a sea of lights covering four soccer fields. They observed a brief silence and organizers laid wreaths at a makeshift shrine dedicated to “martyrs of democracy.”

The crowd also sang the pro-democracy song, “Freedom Flower,” with the lyrics: “No matter how heavy the rain beats, freedom will blossom.”

Organizers claimed 44,000 attended the commemoration, but police put the figure at 19,000. The crowd size was likely hurt by rainy weather in recent days and the lack of major political disputes.

Wang Dan, one of the 1989 protest leaders who was jailed and then exiled to America, said in a taped video message: “We don’t want China to plunge into chaos nor do we want the ruling party to give up power. We only want the Chinese people to live freely and with dignity.”

China’s authoritarian government has stood by the suppression of what it has called “counterrevolutionary” riots, saying it preserved social stability and paved the way for economic growth.

Chinese police monitored Tiananmen Square closely yesterday.

About 2,000 police were on guard in and around Beijing’s “petitioner’s village,” a cluster of cheap hostels popular with people from the provinces who have come to the capital to complain to the central government.

Mr. Wang said in an article published in Hong Kong’s Ming Pao newspaper that he holds out hope China will loosen its political controls.

“Although so far we can’t see any loosening, personally I’m confident that day will come,” he said. “Until the government reverses its position [on the 1989 protests], ordinary people won’t easily forget the crackdown.”

Hong Kong leader Donald Tsang urged his fellow citizens to look at the Tiananmen crackdown practically.

“Mainland China has undergone a level of change that has gained the world’s attention in the past 17 years. These changes have brought much prosperity to Hong Kong … so Hong Kong people can make an objective judgment,” Mr. Tsang said.

Joseph Cardinal Zen of Hong Kong, a fierce democracy advocate, disagreed with Mr. Tsang.

“How can we let it go? Should we just let it slide, forgive, pretend nothing happened? This is irresponsible. The successors of those responsible for the June 4 incident should give an explanation,” Cardinal Zen said.