The U.S. Embassy in Colombia on Friday said it has barred staff from visiting parts of Bogota after Colombian officials warned of a possible rebel attack, but the government denied issuing any such warning, according to Reuters. The embassy said it had received information from Colombian authorities that the largest guerrilla group, the Revolutionary Armed Forces of Colombia, or FARC, planned to attack a mall in the affluent northern section of the capital. "Embassy officials are prohibited from visiting all shopping malls and surrounding areas in northern Bogota," said the warning published on the embassy Web site. "This restriction will be in effect through October 1." Defense Minister Juan Manuel Santos said Colombian authorities were surprised by the announcement and said they had given no information about a possible FARC attack. "The Colombian authorities did not and do not have that information," Santos told local television. "The data comes from a U.S. source and we are evaluating that information." Violence from Colombia's four-decade conflict has decreased under President Alvaro Uribe, who has led a campaign against FARC guerrillas to drive them back from urban areas and key highways they once controlled for kidnapping and extortion. Bogota has seen no major attacks since 2003, when FARC rebels were blamed for killing 36 people in the bombing of an elite social club and tossing grenades into two bars, killing two people and wounding 72 including three U.S. citizens and a German. While violence, kidnapping and crime has dropped in Bogota and other cities and towns retaken by the armed forces, thousands are still killed or forced from their homes by the conflict in rural areas. The FARC, which has 17,000 fighters, says it is fighting for socialism to address inequalities between rich and poor. But Washington brands the group a terrorist organization financed by its involvement in Colombia's vast cocaine trade.