Buenos Aires ( CNN ) -- Police defused a bomb at a Buenos Aires theater Tuesday , a day before a former Colombian president was scheduled to speak there . Authorities offered different assessments of the danger the explosive posed , and when it was set to go off . A judge who investigated the Gran Rex theater said the bomb was set to be detonated around 4:30 p.m. Wednesday afternoon , when former Colombian President Alvaro Uribe is scheduled to speak . `` It was a simple apparatus , but one that could have caused the death of people closest to it , '' Judge Norberto Oyarbide told reporters . Later Tuesday , federal police said the bomb was designed more to cause commotion than serious damage , and had been set to go off on Tuesday afternoon , according to the state-run Telam news agency . `` It was designed to produce shocking sounds , '' police spokesman Commissioner Nestor Rodriguez said . A theater employee alerted authorities after finding the device , Oyarbide said . `` Undoubtedly it looked like a bomb . You could see two pieces , and a cell phone , and it was connected in the middle , '' said Hector Fernandez , a theater employee . Authorities were investigating to determine who placed it in the theater . Colombia 's defense minister condemned the apparent attack attempt and called for an investigation . Last week , a former top official from Uribe 's administration survived an assassination attempt -- a daylight bombing in Colombia 's capital . Uribe was Colombia 's president from 2002-2010 , and was known for his focus on improving security and his tough stance on leftist guerrillas . Uribe is scheduled to speak on at an international entrepreneurs conference Wednesday at the Gran Rex , one of the largest theaters in Buenos Aires . A description of the event on the WOM Leadership Symposium 's website said Uribe would be discussing his role in `` the transformation of Colombia . '' `` In 2002 , he found a country beset by guerrillas and overcome by uncertainty and despair . Eight years later , he handed over a country that was safe , thriving and respected by the international community as one of the most attractive countries for foreign investment , '' the website says . A statement on the website said the conference would continue as scheduled Wednesday . Human rights groups are planning a demonstration Wednesday afternoon near the theater to protest the former Colombian president 's participation in the symposium . An announcement of the protest describes Uribe as a `` true threat to the region , '' arguing that `` in the name of the fight against 'terrorism ' he committed the most atrocious crimes against the Colombian people . '' CNN 's Jose Manuel Rodriguez and journalist Fernando Ramos contributed to this report .
NEW : Police say the bomb was designed to cause commotion . Former President Alvaro Uribe is scheduled to speak in the theater . Authorities are investigating to determine who planted the explosives . Last week a former top Colombian official survived an assassination attempt in Bogota .