Aid workers pulled out of the Goz Amer refugee camp in eastern Chad because it became unsafe after the clashes Wednesday, said Ginette Le Breton of the U.N. refugee agency.
Two refugees, two aid workers and another gendarme were seriously injured in the clashes, she said.
The confrontation occurred a day after paramilitary gendarmes guarding the 12 refugee camps in eastern Chad tried to prevent refugees from selling plastic sheeting they were given by the U.N. refugee agency, she said.
The gendarmes on Tuesday arrested three refugees, prompting others to protest by burning down the community center in a nearby village, she said.
It was unclear why the gendarmes sought to prevent refugees from selling their plastic sheeting, Breton said.
"They sell the sheeting to get some extra money to buy a few things not provided by aid agencies," she said.
"We are talking with the leaders to see what we can do in order to calm down the situation, restart the work in the camp and resume the protection work for the refugees," Breton said.
At least 200,000 Sudanese live in awful conditions in eastern Chad after fleeing violent conflict in Sudan's western region of Darfur, the scene of one of the world's worst humanitarian crises.
An estimated 180,000 people have died in Darfur _ many from hunger and disease _ and about 2 million others have been forced to flee their homes since the conflict began in February 2003.
It erupted when rebels took up arms against what they saw as years of state neglect and discrimination against Sudanese of African origin. The government is accused of responding with a counterinsurgency campaign in which the Arab Janjaweed militia committed wide-scale abuses against the African population.