Haitian lawmakers dismissed the country's prime minister, hoping to defuse widespread anger over rising food prices that led to days of deadly protests and looting.

But violence flared again hours later on Saturday in the capital, where a U.N. police officer was shot dead and a market was set fire.

President Rene Preval, who earlier announced plans to cut the price of rice, immediately said he would seek a replacement for the ousted Jacques Edouard Alexis. The prime minister took office in 2006 with Preval's backing to head a Cabinet meant to unite the poor and fractious nation.

Opposition Sen. Youri Latortue said lawmakers ousted the prime minister because he did not boost food production and refused to set a timetable for the departure of U.N. peacekeepers.

"I think that will satisfy the people," he said after 16 senators out of 27 voted to remove the prime minister.

But about 25 people gathered outside parliament after the dismissal, chanting "Aristide or death," in reference to exiled former President Jean-Bertrand Aristide.

Later a U.N. police officer bringing food to his unit was pulled from a car and killed execution style in Port-au-Prince, U.N. sources said.

The police officer, identified in a forensics report as Nigerian Cpl. Nagya Aminu, 36, drove a marked U.N. vehicle into a crowded clothing market near the cathedral, where he was dragged from the car and shot through the neck, U.N. police spokesman Fred Blaise said.

The incident is the first execution-style killing of a U.N. peacekeeper since the mission came to Haiti in 2004, Blaise said. Passengers in the car, including two Haitian women who work for the mission, were left unharmed.

Witnesses said other Nigerian police officers fired tear gas and warning shots to disperse the crowd before recovering the slain man's body. Two Haitian men were detained for questioning, including a local television journalist who was covering the incident.

When Associated Press reporters arrived shortly after, several market stalls on both sides of the street were on fire. Many in the crowd chanted "Down with MINUSTAH," referring to the U.N. mission by its French acronym.

A leadership change without much delay could help Preval create a government with more legitimacy, said Robert Fatton, a Haiti expert at the University of Virginia.

Without a Haitian army to challenge him and with the backing of the international community, Preval is likely to remain in power despite recent unrest, Fatton said.

But Eduardo Gamarra, director of the Latin America and Caribbean Center at Florida International University, cautioned that a political vacuum has been created and senators might now go after Preval.

The prime minister's ouster reflects frustration over soaring food prices in a nation where most people live on less than $2 a day and chronic hunger had become unbearable in recent months.

The rage erupted in days of violent clashes with U.N. peacekeepers and looting across Haiti that left five people dead in the countryside before abating late Thursday. Protesters even stormed the presidential palace on Tuesday, charging its main gate with a rolling dumpster and yelling for Preval to step down.

Before the death of the U.N. policeman Saturday, U.N. military commander Maj. Gen. Carlos Alberto Dos Santos Cruz told The Associated Press that calm was returning across the country, with some transportation resuming and people going back to work.

Some residents felt their plight would not improve regardless of the dismissal of the prime minister.

"Alexis left? What's the difference?" asked Jackson Aubri, a 28-year-old chicken vendor.

Emmanuel Joseph, a 26-year-old from the seaside slum of Cite Soleil, said residents there are still planning to protest on Monday because they are hungry.

Preval announced that the price of a 50-pound bag of rice will immediately drop from $51 to $43.

He said international aid money will subsidize the effort and that the private sector has agreed to knock $3 off the price of each bag of rice.

Globally, food prices have risen 40 percent since mid-2007. Haiti is particularly affected because it imports nearly all of its food, including more than 80 percent of its rice. Once-productive farmland has been abandoned as farmers struggle to grow crops in soil devastated by erosion, deforestation, flooding and tropical storms.