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Fifty U.S. Marines streamed into the capital Monday to protect the U.S. Embassy and its staff, while government loyalists set flaming barricades to block the road from rebels threatening to move on Port-au-Prince (search ).

The United States made last-ditch efforts at finding a political solution. As an opposition coalition was on the brink of rejecting a U.S.-backed peace plan on the grounds that it did not call for President Jean-Bertrand Aristide (search ) to step down, Secretary of State Colin Powell phoned opposition politicians and asked them to delay responding formally to the plan for 24 hours.

Evans Paul, a leading opponent who once was allied with Aristide, said the coalition agreed the extra time "will perhaps give Mr. Powell a little more time to consider his position ... and give us the assurances we need" on Aristide's departure.

With rebels hoping to seize the capital by Sunday, Cabinet ministers were asking friends for places to hide, senior government sources said. The rebels seized Haiti's second-largest city, Cap-Haitien (search ), with little resistance Sunday and attacked two police stations outside Port-au-Prince.

More than half of Haiti is now beyond the control of the central government. In Cap-Haitien on Monday, rebels hunted down militants loyal to Aristide, accusing them of terrorizing the population in the days before the fall of the northern port city of 500,000.

"I am a brick mason, I didn't do anything wrong," Jean-Bernard Prevalis, 33, pleaded as he was dragged away, head bleeding.

"We're going to clean the city of all 'chimeres,'" said rebel Dieusauver Magustin, 26. Chimere, which means ghost, is used to describe hardcore Aristide militants.

It was not clear what would happen to those detained. One rebel said they were saving them from lynching. But another, Claudy Philippe, said "The people show us the [chimere] houses. If they are there, we execute them."

Thousands of people in Cap-Haitien demonstrated in favor of the rebellion Monday, chanting "Aristide get out!" and "Goodbye Aristide."

Residents went on a rampage of reprisals and looting that began after the insurgents seized the city. Looters stole the 800 tons of food from the U.N. World Food Program warehouse, according to the agency's Andrea Bagnoli, and people torched the colonial mansion of Mayor Wilmar Innocent, who supports Aristide.

Rebel leader Guy Philippe said his men could do nothing to stop the looting, and blamed Aristide's government for leaving most of Haiti's 8 million people hungry and desperate. However, some rebels later fired shots into the air to scatter looters at Cap-Haitien's seaport; at least two looters were hit by rebel gunfire and taken to a hospital.

Philippe said more than 30 residents have volunteered to fight with the insurgents, who have started to replace officials in Cap-Haitien with rebel sympathizers. He said in an interview Monday that he hopes to take Port-au-Prince by Sunday, his 36th birthday.

Remissainthe Ravix, another rebel leader, told The Associated Press there was no turning back.

"We have the weapons and the expertise to take the country," he said. "Nothing can stop us."

The rebels cut cellular telephone service in the city, saying they wanted no communication with Port-au-Prince.

Aid agencies have warned a humanitarian catastrophe is brewing, with 268,000 people who depended on food aid in northern Haiti being the most vulnerable. The International Committee of the Red Cross sent medical supplies and a four-person team.

Aristide's Premier Yvon Neptune said the international community must help save Haiti from "terrorists that are sowing violence and death," but he did not go so far as to ask for peacekeepers.

Neptune appealed to the political opposition coalition to agree to a U.S.-backed international peace plan, which calls for Aristide to share power. Aristide on Saturday accepted the plan.

Western diplomats in Haiti said the United States was searching for a former army officer with the moral authority to shepherd Haiti through Aristide's departure and into a transitional government.

On Monday, Lt. Gen. Herard Abraham, who voluntarily handed power to a civilian government, went on the radio to say "Aristide should make the personally courageous and patriotic gesture to resign, for he no longer controls the country."

Abraham surrendered power in March 1990 to Haiti's Supreme Court justice, allowing a transition that led to Haiti's first free elections in December 1990, which Aristide won in a landlside.

With violence rising both from Aristide supporters and the insurgents, France urged its citizens Monday to leave its former colony. The United States and Mexico told their citizens to get out last week. There are about 30,000 foreigners in Haiti, including about 20,000 Americans, 2,000 French and 1,000 Canadians.

Their rifles at the ready, about 24 Marines in combat gear and helmets rushed off the U.S. Air Force transport plane at Toussaint Louverture International Airport on Monday and ran to make a secure a perimeter around the aircraft before another 30 Marines got off a second plane.

The Marines then drove to the U.S. Embassy in Port-au-Prince in a convoy of trucks and cars. Western diplomats and a Defense Department official said their mission was to protect the U.S. Embassy and its staff.

In Port-au-Prince, hundreds of armed Aristide supporters set up more than a dozen barricades on the road leading north, near the international airport. Their tension was evident as they banged on a car with rifle butts and waved shotguns and pistols at vehicles to force them to stop.

"We are ready to resist, with anything we have -- rocks, machetes," said a teacher guarding one roadblock, who gave his name only as Rincher.

Cap-Haitien is just 90 miles north of the capital, but is a grueling seven-hour drive over potholed roads sometimes reduced to bedrock.

The takeover of Cap-Haitien by only some 200 fighters was the most significant victory since the uprising began on Feb. 5. At least 17 were killed in Sunday's fighting, raising the toll to about 70 dead and dozens wounded in the revolt.

Aristide was wildly popular when he became Haiti's first freely elected leader in 1990 but he has lost support since flawed legislative elections in 2000 led international donors to freeze millions of dollars in aid.

Opponents accuse the former priest of failing to help those in need in the Western Hemisphere's poorest country, allowing corruption and masterminding attacks on opponents by armed gangs. Aristide denies the charges.

Philippe was an officer in the army when it ousted Aristide in 1991 and instigated a reign of terror that ended in 1994 when the United States sent 20,000 troops to end the military dictatorship.