A young man in a white T-shirt walked up to the most sensitive place in China late this afternoon, flung a stack of leaflets into the air and was immediately tackled by eight police officers and shoved into the back seat of an unmarked white Volkswagen Santana.

That simple act of civil disobedience under the portrait of Mao Zedong on the edge of Tiananmen Square sent a momentary jolt of excitement through the hundreds of Chinese tourists milling nearby. Police grabbed most of the fliers, the car sped away and families returned to taking snapshots with Mao.

Such bold political gestures were extremely rare on today's 10th anniversary of the army crackdown on democracy demonstrators near Tiananmen, and it was easy to see why. The impact of the unidentified man's leaflets appeared to be short-lived, but his actions could land him behind bars for an extended period.

The Chinese government views its ability to control what goes on in Tiananmen Square as an important symbol of its national dominance. To ensure that there could be no large-scale protests like those of 1989, the vast concrete expanse was walled off for renovations months ago. That left the wide area beneath the Tiananmen Gate, the entrance to the Imperial Palace on the north of the square, as the main stage for today's bit of political drama. Police were stationed every few yards. Still, despite the risks, several individuals sought to make a point.

The pamphleteer attacked corruption in his essay, which was signed "a Beijing University student."

"Severely punish the cruel history of a large number of corrupt officials, embezzlers of state assets and tax evaders," it read. "Workers are sacred! Democracy is the guarantee."

The essay did not broach the issue of the Tiananmen crackdown, but corruption was a major complaint in 1989. In a separate, earlier incident, journalists saw another man walk to the edge of Tiananmen and open up an umbrella emblazoned with protest slogans. One memorialized the crackdown; another called for the privatization of China's state assets.

After about one minute, police saw through the ruse, grabbed the umbrella-toting activist and dragged him away, but the image was captured by an American photographer.

In the central city of Xian, police detained dissidents Yang Hai, Tang Zhiping and Zhang Jiankang who were planning a private candlelight vigil to mark the anniversary, the Associated Press reported. Nearly all observances today were held in private. Relatives of those killed, and alumni of the 1989 protests, had quiet memorials in houses and at grave sites. China's government-controlled media did not mention today's anniversary.

CAPTION: (Photo ran on page A01) Tens of thousands of people crowd into Victoria Park in Hong Kong to mourn the democracy activists killed in Beijing's Tiananmen Square 10 years ago. China forbade commemorations on mainland but allowed them in Hong Kong.