Manolo Duque, the mayor of Colombia's city of Cartagena, said 20 people died after the collapse of a six-floor building, which was under construction without a license. Duque on Saturday said the Blas de Lezo II building collapse that occurred Thursday at about 11:30 a.m. injured 23 people. Duque said 12 bodies have been identified so far. "As I am from Cartagena and a neighbor of this neighborhood, I am deeply moved by this tragedy," Duque said in a statement. The Cartagena mayor's office said search and rescue operations concluded but cleanup efforts continued Monday. The area near the collapse is closed. The city held a mass on Saturday to pay respects to the dead. Those in attendance observed a minute of silence. "We pray for the 23 injured to have a prompt recovery," Duque said. Colombia's federal attorney general has launched an investigation into the incident. Officials said the first two floors of the nearly completed building were inhabited by residents. Duque said the construction site operated with a fake license.