PEREIRA, Colombia -- Armando Garces was reluctant to leave his mountain village even after right-wing militia members had gone door to door telling residents they had 48 hours to evacuate, or else. He didn't like being ordered to abandon the only home he had ever known.

Then a daylong gun battle erupted between the paramilitary fighters and leftist guerrillas over control of nearby coca crops and transit routes. Mr. Garces' town -- Bajo Calima, nestled in Colombia's Pacific coast rain forest -- was caught in the crossfire between the rebels above the town and militia members below it.

"We hid under our beds all day, and the next morning we were gone," said Mr. Garces, recalling the terrifying day in June when his township became a battleground in the nation's long-running drug wars. "Everyone agreed it was time to look for some other future."

So the 25-year-old woodcutter, his wife, two children and 500 other residents joined Colombia's swelling ranks of the internally displaced. More than 3 million people have been driven from their homes by the long-standing civil conflict between Colombian armed groups vying for political dominance and control of crops related to the nation's drug trade as well as of other agricultural products.

Only Sudan has more internally displaced citizens than Colombia, according to the Norwegian Refugee Council, a human rights group that has tracked the displaced around the globe for the Office of the United Nations High Commissioner for Refugees.

Although Colombia has had a large displaced population for two decades, the numbers have accelerated in recent months, experts say, and a disproportionate number are, like Mr. Garces, Afro-Colombians. They are targeted because they lack political clout and sophistication at a time when their rural homes have become economically attractive.

Ricardo Esquivia, general coordinator of ARVIDAS, an advocacy group for the displaced in Sucre state, said most Afro-Colombians who own such lands either lack full knowledge of their rights or the political power to impose them. One factor working against Afro-Colombians is the 80 percent illiteracy rate in the rural areas where many of them live, said Esquivia, himself an Afro-Colombian.

"They are historically vulnerable and relegated because they have never fully exercised their economic, social and cultural rights," said Jorge Rojas, a leading advocate for human rights and the displaced in Bogota.

Those rights include a constitutional provision that guarantees land title to Afro-Colombian rural communities that have organized loosely as a group and have occupied their property for 10 years or more, said Luis Murillo, a former governor of Colombia's Choco state. Murillo, also an Afro-Colombian, estimates that 1 million Afro-Colombians, or one-third of those living in rural areas, have been forced from their lands.

The growing number of displaced has much to do with the changing logistics of Colombia's multibillion-dollar cocaine trade. The success of spraying programs sponsored by the U.S. government to eradicate coca leaf production in Colombia's Amazon basin has caused a shift in coca farming to more remote areas.