By JONATHAN M. KATZ, Associated Press April 8, 2008

PORT-AU-PRINCE, Haiti - U.N. peacekeepers fired rubber bullets and tear gas into a crowd that gathered outside the presidential palace Tuesday during the second consecutive day of protests over soaring food prices.

Fritz Longchamp, chief of staff to President Rene Preval, said some protesters were trying to break down the palace gates before the U.N. troops moved to establish a security perimeter around the building.

Longchamp said Preval was at work inside the palace.

Witnesses said a Haitian news photographer was injured and taken to a hospital.

Unrest over the rising cost of living began last week, when Haitians burned cars and attacked a U.N. police base in the southern city of Les Cayes. At least five people have been killed there.

The demonstrations reached the capital Monday, when thousands marched past the National Palace, some of them crying out "We're hungry!"

The protests intensified Tuesday, as demonstrators barricaded streets and pelted a marketplace with rocks.

Haitians are particularly affected by food prices that are rising worldwide. Eighty percent of the population lives on less than US$2 (euro1.27) a day. The cost of staples such as rice, beans, fruit and condensed milk has gone up 50 percent in the past year, while the cost of pasta has doubled.

The U.N. World Food Program made an urgent appeal on Monday for donations to support its operations in Haiti, the poorest nation in the Western Hemisphere. U.N. Secretary-General Ban Ki-moon warned last week that the food crisis could threaten Haiti's already fragile security.