LAHORE , Pakistan ( CNN ) -- A suicide bomber killed at least 23 people and injured more than 58 others after detonating an explosive outside a court in Lahore on Thursday , police said . A rescuer helps an injured man following a suicide bomb attack in Lahore . The exact number of casualties varied , but state-run news agency the Associated Press of Pakistan said 22 police officers and one passerby were killed . Reports of another explosion triggered a dash toward a supposed second blast site , but those reports proved unfounded , said Aftab Cheema , senior superintendent of Lahore police . The suicide blast occurred in the city 's commercial district , moments before lawyers were set to begin a rally outside the high court in the eastern Pakistani city to protest the rule of President Pervez Musharraf . No one immediately claimed responsibility for the attack . Caretaker Prime Minister Mohammadmian Soomro said in a statement that those who committed this `` cowardly act '' were `` neither believer of any religion nor of any human ethics . '' Police said about 100 uniformed and plainclothes officers were at the scene ahead of the rally when the bomb went off about 11:45 a.m. Pakistan time ( 6:45 a.m. GMT ) . The bomber was approaching a police barrier when officers stopped him , said Cheema , and the man then blew himself up . Ahsan Bhoon , president of the Lahore High Court Bar Association , said lawyers had just completed a meeting and were headed out of the courthouse to participate in the rally when he heard the blast . Bhoon said he saw bodies scattered everywhere . At least 15 of them were lifeless . A second lawyer , Khurram Khosa , said he began picking up bodies of the dead and noticed all but one of them clad in the green uniform of police officers . Many of the wounded were taken to Mayo Hospital in Lahore , said medical superintendent Fayyaz Ahmad Ranjha . Two remained in critical condition but the rest were likely to survive , Ranjha said . Footage from the scene painted a chaotic picture , with baton-wielding police working to beat back a crowd that was trying to get a closer look at a burned-out white vehicle . Officers cordoned off the area , while rescue workers carrying stretchers with wounded victims sidestepped shards of glass that littered the street from broken car windows . `` Lahore is typically a calm city , '' local journalist Todd Baer said . `` This is one of the few places in Pakistan that did not have rioting ( after the assassination of former Prime Minister Benazir Bhutto ) . So people here are very tense right now . '' In recent months , Pakistan has been besieged by a wave of suicide attacks that has claimed several hundred lives . The blast comes a day before the start of the month of Muharram , a holy period of mourning , when religious tension are high . It also follows the death of Bhutto , who was killed at a rally in Rawalpindi , south of the Pakistani capital Islamabad , on December . 27 . While the cause of her death is still unclear , a bomber blew himself up near her limousine and videotape showed a gunman present . Lawyers in Lahore have been holding rallies every Thursday to protest the government 's crackdown on the judiciary and imprisonment of lawyers and judges across the country . Meanwhile , Bhutto 's Pakistan People 's Party said it had written to the Pakistan government urging it to request an independent United Nations inquiry , The Associated Press reported on Thursday . The PPP warned that if the government failed to do so within 48 hours , the party would approach the U.N. directly . E-mail to a friend . CNN 's Mohsin Naqvi , Leone Lakhani , Ingrid Formanek and journalist Todd Baer contributed to this report . Copyright 2008 CNN . All rights reserved.This material may not be published , broadcast , rewritten , or redistributed . Associated Press contributed to this report .
NEW : Blast outside Lahore court kills at least 23 people and injures 58 others . Suicide bomb exploded as lawyers were set to begin protest rally outside high court . A man blew himself up after being stopped by police at a security barrier . There were reports of a second blast , but these proved to be unfounded .