President Bush (search) on Wednesday authorized the United States to continue helping Colombian authorities ground or even shoot down planes suspected of carrying illegal drugs.

The program was put on hold in 2001 when a small plane carrying American missionaries was shot down over Peru. Bush resumed surveillance flights over Colombia (search) on an annual basis in August 2003, but the program remains on hold in Peru.

The Colombians are working to minimize the loss of innocent life, Bush said Wednesday in a memo to Defense Secretary Donald H. Rumsfeld and Secretary of State Condoleezza Rice (search), who oversees the program.

Colombia is the world's largest producer of cocaine and it supplies most of the heroin found in the United States. Strategies for reducing the drug trade were a major topic of conversation when Bush hosted Colombia President Alvaro Uribe (search) at his Texas ranch earlier this month.

The missionary plane was mistakenly shot down in 2001 by a Peruvian warplane guided by U.S. intelligence operatives. Two Americans — Veronica Bowers, 35, of Muskegon, Mich., and her 7-month-old daughter, Charity — were killed.

A U.S.-Peruvian inquiry concluded that procedural errors, language problems and an overloaded communications system contributed to the downing. The U.S. crew later realized the flight was innocent, but couldn't stop the Peruvians from shooting.

The program resumed over Colombia in August 2003 under stricter procedures: Suspicious flights must first be ordered to land and warning shots fired before it can be shot down. Also, no plane can be shot down by the air force without a direct order from the commander of the Colombian Air Force.