Alvaro Uribe (file photo)

Colombian President Alvaro Uribe has vowed to increase efforts to destroy plants used to make cocaine, in order to choke leftist rebels' drug trafficking income.

President Uribe Wednesday said the government will not rest until "the last coca plant" is eradicated near Macarena National Park, in an operation beginning January 20. The park is close to a region controlled by the Revolutionary Armed Forces of Colombia, or FARC.

Mr. Uribe's comments come just one day after rebel forces killed 29 soldiers standing guard as workers destroyed coca crops, used to make cocaine.

The 17,000-strong FARC, and a smaller guerrilla group known as the ELN, have been engaged in a deadly 41-year civil war to topple the government. The rebels fund operations mainly through drug trafficking.

Colombian President Alvaro Uribe, who is running for re-election in next May's presidential vote, has stepped up military efforts against FARC forces in the region.