Leftist rebels ambushed crews eradicating coca plants in a Colombian national park Monday, killing seven police guards and wounding seven other police and a worker, officials said.

The eradication teams are part of a high-profile mission to rid the Sierra Macarena National Park of coca, the base ingredient of cocaine.

The mission was announced by President Alvaro Uribe following the December killing of 29 soldiers near the pristine park, 100 miles south Bogota and a longtime stronghold for the Revolutionary Armed Forces of Colombia, or FARC.

The leftist rebels have been trying to overthrow the government for more than four decades and in recent years have taken up drug trafficking to finance their struggle.

President Uribe lamented the police officers' death and vowed to send another battalion of soldiers so that eradication teams could safely "eliminate every last coca plant in the national park."

U.S.-owned fumigation planes spray weed killer over tens of thousands of acres of Colombian coca fields each year, but bypass the country's 36 nature parks due to environmental concerns.