five people were wounded when a bomb exploded as they were walking near a shopping center in Bogota

five people were wounded when a bomb exploded as they were walking near a shopping center in Bogota, Colombian police said.An urban cell of the Revolutionary Armed Forces of Colombia, or FARC, guerrilla group planted the 1.5-kilo (3.3-pound) bomb that exploded Monday night, Metropolitan Police chief Gen. Rodolfo Palomino said.
The bomb contained "shrapnel that shattered windows and damaged some stores," the police chief said.The blast occurred at 9:30 p.m. Monday at an appliance store in the Punto 169 shopping center, which is close to one of the TransMilenio rapid transit system's stations, but service was not affected.Three people wounded by flying glass were taken to a hospital for treatment, while the other two were treated at the scene.The explosion damaged at least four nearby houses and several stores.The Autopista Norte, one of Bogota's main expressways, was closed for a couple of hours while police investigated the bombing.Investigators said they believed the bomb was planted by the FARC as part of a scheme to extort money from merchants."Intelligence work can establish that this was an attack by the FARC," Palomino said, adding that merchants had received threats that something would happen unless they paid.Authorities are offering a reward of 50 million pesos (some $22,000) for information leading to the arrest of those behind the bombing, Palomino said Tuesday.Police have stepped up security on the Bogota mass transit system to prevent further attacks.Several bombings have occurred in Bogota in the second half of this year, with the most serious attack taking place on Oct. 4, when a woman died in a blast at a financial firm.The FARC, Colombia's oldest and largest leftist guerrilla group, was founded in 1964, has an estimated 8,000 to 17,000 fighters and operates across a large swath of this Andean nation.President Alvaro Uribe's administration has made fighting the FARC a top priority and has obtained billions in U.S. aid for counterinsurgency operations.The FARC, whose leader is Alfonso Cano, has suffered a series of blows this year.On July 2, the Colombian army rescued former presidential candidate Ingrid Betancourt, U.S. military contractors Thomas Howes, Keith Stansell and Marc Gonsalves, and 11 other Colombian police officers and soldiers.The FARC had been trying to trade the 15 captives, along with 25 other "exchangeables," for hundreds of jailed guerrillas.The rebels' most valuable bargaining chip was Betancourt, a dual Colombian-French citizen the FARC seized in February 2002 whose plight became a cause celebre in Europe.FARC founder Manuel Marulanda, who was known as "Sureshot," died on March 26.On March 1, Colombian forces staged a cross-border raid into Ecuador, killing FARC second-in-command Raul Reyes and setting off a regional diplomatic crisis.Ivan Rios, a high-level FARC commander, was killed March 7 by one of his own men, who cut off the guerrilla leader's hand and presented it to army troops, along with identification documents, as proof that the rebel chief was dead.A succession of governments have battled Colombia's leftist insurgent groups since the mid-1960s.In 1999, then-President Andres Pastrana allowed the creation of a Switzerland-sized "neutral" zone in the jungles of southern Colombia for peace talks with the FARC.

After several years of fitful and ultimately fruitless negotiations, Pastrana ordered the armed forces to retake the region in early 2002. But while the arrangement lasted, the FARC enjoyed free rein within the zone.

The FARC is on both the U.S. and EU lists of terrorist groups. Drug trafficking, extortion and kidnapping-for-ransom are the FARC's main means of financing its operations.