By LYDIA POLGREEN and TIM WEINER
 
ORT-AU-PRINCE, Haiti, March 2 — Haiti veered toward anarchy on Tuesday when a rebel leader proclaimed himself chief of a revived army, threatened to jail the prime minister and sent his men to search out allies of the deposed president, Jean-Bertrand Aristide.

"I am the chief," the rebel leader, Guy Philippe, declared at a news conference, "the military chief."

"The country is in my hands," he proclaimed as he met hundreds of supporters near the palace that last held Mr. Aristide, the constitutionally elected president. Mr. Aristide left Haiti early Sunday for the Central African Republic after a shove from the United States.

In the absence of any other authority, Haiti seemed to be falling into the clutches of a self-appointed armed junta. Although American officials denounced the armed rebels and said they should have no role in ruling Haiti, the Americans did not take steps to confront them.

Col. David H. Berger, the Marine Corps commander here, said his troops would not act as police officers. "I have no instructions to disarm the rebels," he said.

The contingent of marines dispatched to Haiti by President Bush grew to 450 today, officials said. They stuck mostly to the airport and the National Palace. Several guarded Prime Minister Yvon Neptune's residence. About 100 French and Canadian troops have also arrived, and The Associated Press reported that Chile would be sending 300 soldiers.

The rebels' power grab was met with silence or muted support by members of the political opposition to the Aristide government; inaction from United Nations diplomats, who have promised to form a multinational peacekeeping force for Haiti; and contempt from Washington, where officials dismissed Mr. Philippe as a nonentity.

"He is not in control of anything but a ragtag band," an assistant secretary of state, Roger Noriega, told the Senate Foreign Relations Committee.

But no one else appeared to be in charge of Haiti. The armed rebels reigned in Port-au-Prince, having seized government installations on Monday, and vowed to resurrect the army.

The new president, Boniface Alexandre, who is chief justice of the Supreme Court, has not been seen in public since a news conference on Sunday when he announced he would take office. He appeared pale and shaken, and unsure of his role.

His authority was uncertain, too. The Constitution says his appointment requires ratification by the Legislature, which was dissolved in January. The Constitution also provides for presidential authority to be held by a council led by the prime minister.

Mr. Neptune, the prime minister, whom Mr. Philippe threatened to arrest, met Tuesday with the American ambassador, James B. Foley, the White House said.

Mr. Philippe paraded through the streets like a conqueror. His men scoured the slums, which formed Mr. Aristide's strongest political base, seeking out Aristide loyalists.

The rebels sought to fill the vacuum left by Mr. Aristide's fall, and were moving faster than what remains of the government of Haiti.

"It is an absolutely failed state — no institutions, no rule of law, no spirit of compromise, no security," said Robert Pastor, director of the Center for Democracy and Election Management at American University. "There is no state right now."

Mr. Pastor has monitored elections here since 1987.

Complicating the political chaos, Jean-Claude Duvalier, Haiti's former "president for life," said in Miami that he planned to return to Haiti, where he maintains a small group of nostalgic supporters.

His rule began when his father, François, the dictator known as Papa Doc, died in 1971, and it ended when the army overthrew him in 1986. During the three-decade Duvalier dynasty, the government killed thousands of opponents and stole many millions from Haiti's treasury.

The army, which earned a reputation for brutality and corruption, overthrew Mr. Aristide in 1991. He returned, backed by American force, in 1994, and dissolved the army in 1995.

Many of the armed rebels who stormed the capital on Monday are army veterans. Some led military-affiliated death squads that killed Aristide supporters in the 1980's and 90's. Others, like Mr. Philippe, were military-trained police captains.

The United States is trying to help form a "council of elders," including the so-called unarmed opposition, a squabbling group of political elites "united only by their hatred for Aristide," said Robert Maguire, director of the Haiti Program at Trinity College in Washington.

Now that Mr. Aristide has gone, so has the unarmed opposition's unifying principle.

The prospect of a revived Haitian Army and a country run by armed rebels terrifies the residents of La Saline, a vast slum and Aristide stronghold in the capital.

"The army and the people with money always were against the poor," said Ernseau Bolívar, 23, a student who lives in La Saline. "President Aristide made a lot of mistakes, it is true. But he was always representing people of the poor, people of my class. Traditionally the political class used the army to oppress us. That is what we fear."

Mr. Bolívar said he thought Mr. Aristide had been forced out by American pressure. He called the president's fall a coup. "We elected Mr. Aristide," Mr. Bolívar said. "How can the Americans now come and take him away? What about our Constitution? What about our laws?"

Lawlessness was the rule in parts of the capital on Tuesday. Looting continued at the port, even as American marines stood watch nearby.

Despite the rebels' vow to restore order, violence continued. Six bodies of people killed by gunshot wounds were brought to the morgue, bringing the total stored there after the violence over the week to about 25.

While many in the crowds greeting the rebels appeared joyous, they were also raucous. Early in the afternoon, Mr. Philippe appeared on the balcony of the former headquarters of the Haitian Army, which sits adjacent to the palace and was renovated into a museum in honor of Haiti's 2004 bicentennial. He flashed victory signs to the crowd.

A moment after he stepped away, a soldier began tossing art from the museum into the street, beginning with a sculpture of a casket with a figurine inside. It shattered as it hit the ground and the crowd roared. More paintings followed, and someone set the pile of art aflame.

Inorel Delbrun, an art collector who had come hoping to catch a glimpse of the rebel leader, was horrified.

"This is Haitian art," Mr. Delbrun said. "It hurts to see it destroyed. This is our culture."