PORT-AU-PRINCE, HAITI, JULY 10 -- Tens of thousands of Haitians demonstrated noisily but peacefully in the capital today, calling for the removal of the military-led provisional government of Lt. Gen. Henri Namphy.

The protest, which appeared to include 20,000 to 25,000 people at its height, dwindled during the afternoon before being broken up by tear gas at the National Palace, seat of the government. Fears of violence, which would risk re-escalating the political crisis here, were not realized.

Both the authorities and the ad hoc opposition committee that has led 12 days of nationwide protest appeared to hold back from moves that would risk confrontation. Authorities kept police and troops in their posts, while the protest organizers directed their march at the city hall rather than the more sensitive National Palace or Army headquarters.

A major theme in protest slogans was opposition to the United States, which yesterday emphasized its support for Namphy if he holds to his promise of free elections for a government to be installed next February. The demonstrators, mostly young people from the city's poor neighborhoods, shouted "Down with America" and condemned U.S. "imperialism."

The protest leaders rejected U.S. government statements yesterday that the Namphy government is committed to free elections. "The Americans believe you have a democratic process whenever you have elections," said protest leader Victor Benoit. Benoit said Haitians have no confidence in elections planned by Namphy and would boycott any such vote.

At midmorning, the main police headquarters for downtown Port-au-Prince was relaxed. Dozens of uniformed officers lounged, playing dominoes or watching shoppers on the Boulevard Dessalines, outside. A few dusty gas masks hung from nails on a wall.

The post's commander, Maj. Rosney Casimir, dressed in casual civilian clothes, laughed off questions about possible violence. "It will be a peaceful demonstration, and it's the people's right," he said, "so we are not going to do anything."

A few minutes later, the mood changed as the mass chants of approaching protesters could be heard. Nervous policemen scrambled for steel helmets and crowded onto a balcony to watch a river of protesters, banners and signs flow slowly toward them.

Casimir emerged in his uniform just as the crowd arrived, with many angrily shouting insults at the police. He ordered other officers back to the station's doorway and stood smiling and waving to the crowd as though sharing a joke with them.

After the main rally ended, more than a thousand protesters marched spontaneously to the National Palace and taunted soldiers on guard. When a protester threw a wreath commemorating the 23 killed during Haiti's current political crisis into a guard house, troops launched tear gas grenades, dispersing the crowd.