Bogota, Colombia ? Colombia’s military pushed deeper into a former rebel safe haven Tuesday as guerrillas intensified sabotage attacks and kidnappings. The mayor of a town just outside the zone said he was the target of a failed assassination attempt by rebels.

Puerto Rico Mayor Walter Castro said two of his bodyguards were shot to death in the attack on him as he left the town’s church. Puerto Rico’s two previous mayors were killed by rebels.

Rebels of the Revolutionary Armed Forces of Colombia, FARC, check cars at a roadblock near San Vicente del Caguan, the main town in the former rebel safe haven in southern Colombia. Several people were kidnapped by the rebels Tuesay at roadblocks.

Five other people died in separate attacks around the country blamed on the Revolutionary Armed Forces of Colombia, or FARC. Four police officers and a child were killed in an ambush and an attack on a small town. Two people were kidnapped at a FARC roadblock, army officials said.

Nineteen people were kidnapped at a FARC roadblock, though nine women, children and elderly men were released Tuesday evening, according to a report by Caracol Television, which broadcast interviews with the freed hostages.

Witnesses reported FARC rebels also killed seven civilians during the weekend in the town of La Macarena one of five inside the former rebel sanctuary as the guerrillas retreated ahead of an army advance.

There was no new word Tuesday on the fate of Colombian presidential candidate Ingrid Betancourt, abducted Saturday at a rebel roadblock along with her campaign manager.

Interior Minister Armando Estrada said the government had ruled out swapping rebel prisoners for kidnap victims. The guerillas reportedly have expressed readiness to trade Betancourt and five members of congress for captured guerrillas.

Troops moving to retake the former rebel enclave reached La Macarena, a dusty outpost, for the first time Tuesday and were investigating the reported killings, said army spokesman Capt. Jorge Florez.

Rebels, meanwhile, kept up a bombing campaign against bridges and power stations begun last week after President Andres Pastrana ended the peace process and launched the military offensive to retake the zone.

The president ceded the area, a Switzerland-size swath of southern ranchland and woods, three years ago in hopes the rebels would end their 38-year war.

The FARC dynamited a bridge about 31 miles north of Bogota on Tuesday, said Alvaro Cruz, the governor of Cundinamarca State.

The government offensive was launched after Pastrana canceled the peace process when a popular senator was taken hostage after an airliner hijacking.

In Washington, White House spokesman Ari Fleischer expressed support Tuesday for Pastrana’s actions.

“Regrettably, the goodwill of the Pastrana government and the Colombian people has not been reciprocated by the FARC,” Fleischer said.

Pastrana has asked the United States to lift restrictions that allow him to use U.S. military assistance only in the fight against drugs. He hopes to win approval to use helicopters and other U.S.-donated equipment against the FARC.

Fleischer said the United States has legal constraints but is trying to determine “where we can be helpful, how we can be helpful.”

U.S. aid is currently earmarked for counternarcotics purposes. But with FARC rebels increasingly involved in the drug trade, the lines between fighting drugs and Colombia’s insurgency are blurring.