The Bush administration supported Colombian President Andres Pastrana in his decision to crack down on rebels.

"We've always expressed our support for President Pastrana," State Department spokesman Richard Boucher said Thursday. "We've always said these are decisions for him to make."

Pastrana canceled peace talks and ordered the bombing of positions controlled by leftist guerrillas.

Another administration official, asking not to be identified, said no consideration was being given to using U.S. troops in a combat role.

The official said the administration is reviewing measures it might take to help Colombia within the limits imposed by the Congress.

U.S. military assistance is generally limited by law to assisting Colombia's counternarcotics campaign.

Among the options under consideration are enhanced intelligence sharing and a speedup in the delivery of spare parts for U.S. helicopters used by the Colombian military in the drug fight.

The administration also may take steps to permit increased aerial spraying of narcotics fields -- something the Colombians have been seeking.

This could impair the rebels' war-fighting capability because they derive much of their income from the drug trade.

The deadly attacks by FARC guerrillas since Jan. 20, when they agreed to make the peace process work, are horrible, a senior U.S. official said.

Also, he cited the hijacking of an airplane Wednesday and the kidnaping of a Colombian senator. "We can understand President Pastrana's frustration," the official said.

Steve Lucas, spokesman for U.S. Southern Command, said there are about 250 U.S. military personnel, 50 civilian employees and 100 civilian military contractors in Colombia.

Also, State Department employees and contractors, who fly and maintain planes and helicopters used for drug crop eradication, also are in the South American country.

Congress has restricted U.S. personnel in Colombia to 400 military and 400 civilian.

Lucas said U.S. personnel provide military advice to the ambassador and staff and tactical advice and training for Colombian anti-narcotics operations.

Though the administration and Congress had expressed interest in broadening the U.S. military role in Colombia, "We are still operating under the existing guidance which is U.S. assistance to Colombia is limited to counternarcotics," Lucas said.

The spokesman declined to say where in Colombia most of the U.S. personnel are based, but said "generally speaking, they are in secure areas -- as secure as things get in Colombia -- and we constantly address the potential threat to U.S. personnel and move them accordingly."