PORT-AU-PRINCE (Reuters) - Four people were killed in southern Haiti when demonstrators protesting the high cost of living clashed with security forces, a local official said on Friday.

The United Nations said protesters rioted in the town of Les Cayes on Thursday, burning shops, shooting at peacekeepers and looting containers at a U.N. compound.

“At least four people have been killed and about 20 others wounded,” said Gabriel Fortune, a senator from the southern region, who condemned the violent behavior of the demonstrators.

“The movement started well, but it was spoiled by the intrusion of a number of criminals that have nothing to do with the legitimate demands of the population,” said Fortune.

Food prices in Haiti, the poorest country in the Americas, have soared in recent months, stoking anger against the government of President Rene Preval.

Preval’s election in 2006 raised expectations that the country would finally start on the path to stability after decades of turbulence, culminating in the February 2004 ouster of former president Jean-Bertrand Aristide.

Les Cayes was tense after the riots and the U.N. force trying to maintain peace in the volatile Caribbean country sent 100 peacekeepers as reinforcements, the U.N. statement said.

A small group of protesters broke into the U.N. compound in Les Cayes, damaging the main gate and ignoring warning shots from peacekeepers, the statement said.

“The protesters also burned shops in Les Cayes and threw rocks and fired weapons at some of the blue helmets during the night.”

At least two U.N. vehicles were burned, demonstrators threw rocks at cars and at least one woman was raped, according to local officials and radio reports.

“This hunger is unbearable and the government has to act now, otherwise we will burn down and destroy everything,” a demonstrator shouted into a local reporter’s microphone.

At a news conference, Prime Minister Jacques Edouard Alexis denounced what he called manipulation of the protests.

“We know that these demonstrations have been infiltrated by individuals linked to drug dealers and other smugglers,” he said, calling on the protesters to stop the demonstrations.

Alexis said the government had immediately made available about $10 million to help fight the high cost of living. He announced job creation and credit programs and said food would be distributed and fertilizer prices cut in half.

Haiti, which shares the island of Hispaniola with the more prosperous Dominican Republic, has been relatively tranquil recently, although a resurgence in kidnappings and crime has alarmed the United Nations.

Just under 9,000 Brazilian-led U.N. peacekeepers and civilian police are stationed in Haiti.

U.N. Secretary-General Ban Ki-moon this week called on the international community and Haiti’s leaders to keep up their efforts to bring stability to the country. “The potential for regression remains,” he said in a report.