By TIM JOHNSON
 Herald Staff Writer

 BOGOTA, Colombia -- In a lethal resurgence of urban terrorism, a large bomb
 ripped through an army anti-kidnapping facility in Medellin on Friday, killing as
 many as 10 people, injuring about 30 others and nearly leveling a whole block,
 police said.

 The bombing was the deadliest in Medellin since Pablo Escobar, chieftain of a
 cocaine cartel based in that city, led a terror campaign that ended with his death
 in 1993.

 Urban militias of the Revolutionary Armed Forces of Colombia (FARC), a leftist
 insurgency, set off the 3:15 p.m. blast in reprisal for raids earlier in the day
 against suspected guerrilla kidnappers, army Gen. Eduardo Herrera said.

 Police confirmed six deaths, but the RCN evening television news said 10 people
 had died.

 Destruction was heavy. Authorities said at least 37 cars, seven motorcycles and
 six homes were destroyed. Scores of other houses were damaged, metropolitan
 police commander Luis Alfredo Rodriguez said.

 The bomb exploded in a white pickup truck parked near the army anti-kidnapping
 facility known by its initials as GAULA. Sirens wailed as rescuers took the injured
 to seven hospitals in Medellin, Colombia's third-largest city.

 Among the dead or missing were a federal prosecutor, his secretary and an agent
 for the Colombian equivalent of the FBI, all of whom worked with the army
 anti-kidnapping unit, Rodriguez said.

 Two soldiers and two judicial investigators remained missing under rubble.

 ``It was very strong,'' an army source told The Herald. ``The whole block was
 practically leveled. We still don't know how much explosives were in the truck.''

 The blast shook a tree-lined residential neighborhood near the city's soccer
 stadium and three blocks from the army's Fourth Brigade, which was racked by a
 car bomb last August.

 An army statement said the military anti-kidnapping unit had conducted 11 raids
 earlier in the day against urban militias of the FARC, making seven arrests.

 FARC rebels abducted more than 600 people last year. Collecting ransom
 through kidnapping is a major source of revenue for the guerrillas.

 Terrorism by FARC urban guerrillas appears to be on the rise. In the past three
 months, guerrillas have launched homemade mortars at the army artillery school
 and the military academy in Bogota, as well as the air force academy in Cali.