(refiles to fix typo in second paragraph)

BOGOTA, Aug 27 (Reuters) - Nine people, including four children, were shot and killed at a farm in southern Colombia where the owner had been threatened by guerrillas over extortion payments, police said.

The killings on Sunday in Putumayo province near Ecuador's border were the second massacre in a week attributed to the Revolutionary Armed Forces of Colombia, known as FARC, the country's largest guerrilla force fighting a four-decade conflict.

"The information we have at the moment is the owner of the farm ... had been threatened by the FARC," Police Col. Harold Lara told local radio. "From what we know, most of the bodies were shot in the head."

Authorities last week blamed the FARC for singling out and murdering five people in a northern town after going door to door with a list of names, including those of former paramilitaries who fought the rebels before demobilizing.

Violence from Latin America's oldest guerrilla insurgency has eased under President Alvaro Uribe's U.S.-backed security campaign, especially in cities. But the FARC, which began as a peasant army, is still strong in rural areas, helped by funds gained from the country's cocaine trade.

AlertNet news is provided by