BY NANCY SAN MARTIN, SUSANNAH A. NESMITH AND MARTIN MERZER

PORT-AU-PRINCE -- Fearing an imminent rebel attack, Haitians loyal to President Jean-Bertrand Aristide built ramparts around the presidential palace Thursday as the increasingly isolated Aristide insisted he would serve his entire term of office.

Radio reports asserted that Aristide stood on the brink of resigning, but he forcefully denied that. As darkness fell, he retained his tenuous grip on power.

''I will leave the palace on Feb. 7, 2006, which is good for democracy,'' he told CNN.

In Washington, Secretary of State Colin Powell openly questioned Aristide's ability to remain in office, a major diplomatic setback for the Haitian leader. But there was no sign that the Bush administration would act soon to quell the violence.

''Whether or not he is able to effectively continue as president is something he will have to examine carefully in the interests of the Haitian people,'' Powell said.

And so, the crisis deepened throughout the day and into the night.

One knowledgeable Haiti expert in Washington told The Herald that the White House fears ''a narco-state like Somalia'' if the rebels take over, but events were unfolding rapidly.

Diplomats met in Washington and at the United Nations, seeking a solution. More than 100 foreigners, shielded by armed U.S. security agents, fled the country. American Airlines suspended all flights between the United States and Haiti until March 3.

At the United Nations, the Security Council met for more than three hours but could agree only on a nonbinding statement calling for the creation of an international police force to support a government of national unity in Haiti.

French U.N. Ambasador Jean-Marc de la Sablire told The Herald there was no support ''at this time'' for an official vote authorizing such a force. The Bush administration is insisting on a political settlement in Haiti before peacekeepers can be sent in.

In South Florida, the Coast Guard said it intercepted more than 500 Haitian migrants on about a dozen vessels this week, and Powell acknowledged ''a spurt'' in the migrant flow from Haiti.

A Coast Guard spokesman said the number represented an increase in activity but did not necessarily herald a mass migration. The migrants were aboard Coast Guard cutters and probably will be returned to Haiti, the spokesman said.

Back in Port-au-Prince, the drumbeat of rebel threats grew louder.

REBEL LEADER'S VIEW

Rebel leader Guy Philippe asserted, as he has repeatedly in recent days, that an undisclosed number of insurgents were en route to the capital and gathering for an attack.

Their primary objective: the presidential National Palace.

Philippe said his main concern was that he might not get to Port-au-Prince before Aristide falls.

''I don't want him to leave. I want him to be arrested,'' Philippe told The Herald during an interview at his base in the captured northern city of Cap Haitien. ``If the people find him, I think they will kill him, but we won't let him have such a sweet end.''

The fighting, which erupted Feb. 5, already has claimed at least 80 lives. Moving quickly, rebels have ejected Aristide's demoralized police force -- the nation does not have an army -- from nearly all of northern and central Haiti.

In a radio broadcast Thursday, Philippe said: ``It will be over very soon.''

A few hours later, several hundred Aristide supporters massed in front of the presidential palace. Most were young men. Many wore bandannas of the Haitian flag, and some carried guns and machetes.

Teenagers driving bulldozers and forklifts started constructing defenses around the place. They yelled, ''Aristide for five years,'' a reference to his full term of office.

''If he doesn't have five years, we will cut heads and burn houses,'' said Sevelin Pierre, 30.

Most streets were nearly deserted, and many shop owners shuttered their businesses. Long lines formed at the few open gas stations.

No independent sightings of rebel movements were reported, but the Haitian Liberation Front was widely rumored to have undercover agents already in the capital.

''I already have a national army,'' Philippe said in accented but perfect English as he sat at a poolside table, eating a late lunch of goat meat and rice at a Cap Haitien hotel.

In Port-au-Prince, security forces from the U.S. Embassy supervised the evacuation of 114 nonessential personnel and dependents from the U.N. Development Program.

Security officers escorted the U.N. entourage to the airport for a chartered flight to the Dominican Republic.

Meanwhile, several sources told The Herald that Aristide planned strategy late Wednesday with armed loyalists -- known as chiméres, after a mythical dragon -- in their stronghold of Cité Soleil, though details of the discussion remained unknown.

Some chiméres hinted they might be willing to accept Aristide's departure and lay down their weapons. But only if the rebels ''give us the respect we deserve,'' said Maestro Fritz Neur, 24.

On the diplomatic front, officials from Jamaica and other Caribbean nations urged the U.N. Security Council immediately to send a peacekeeping force to Haiti.

But the council, following the lead of the Bush administration, indicated that it would await a settlement between Aristide and his opponents -- or the replacement of his government.

'Anybody who looks at this says, `What is it we're getting into?' '' Powell told a congressional committee in Washington. ``We've got to get into something that looks like it's a political solution. And that has not yet emerged.''

`PEOPLE ARE BLEEDING'

Aristide's political opponents rejected a peace plan earlier this week, a move that deeply frustrated the Bush administration, which warned them that the United States would not endorse a peacekeeping force until they changed their minds, The Herald learned.

''They want us to do for them what they could not do at the ballot,'' said the knowledgeable Haiti expert, who requested anonymity and is involved in the consultations in Washington. ``But they are risking the possibility that the armed rebels will beat them to the palace, and then what do they do?''

Still, the administration was harshly criticized by many Democratic and black leaders, including some in South Florida, who accused the White House of indifference.

''Today, the people are bleeding,'' North Miami Councilman Jacques Despinosse said during a news conference called by Haitian-American activists in Miami's Little Haiti. ``Maybe Haiti does not have oil or gas and things you need, but we have human beings. Do the right thing.''

Herald staff writers Trenton Daniel and Marika Lynch in Port-au-Prince, Frank Davies in Washington, and Jacqueline Charles, Ina Paiva Cordle and Elaine de Valle in Miami contributed to this report.