Authorities in southern Sindh Province, of which Karachi is the capital, have declared a public holiday to mourn the dead, let tempers cool, and control the mob violence that erupted after a suicide bombing rocked a Shi'ite religious procession, killing at least 43 and injuring more than 100.
The procession, held to mark Ashura, commemorates the seventh-century martyrdom of Imam Hussein, grandson of the Prophet Muhammad.
Municipal authorities say that more than 1,000 shops and dozens of automobiles were torched after the bombing, and claim that those who planned the suicide attack also anticipated the mob violence.
The bomber targeted the Shi'ite procession as it passed along Mohammad Ali Jinnah Road -- a key commercial center that also serves as a key transit hub for supplies to NATO forces in neighboring Afghanistan.
"Enraged protesters set fire to shops following the bomb blast,” said Mohammad Dilawar, the mayor of a Karachi district. “About 1,000 shops have been burned, causing losses of billions of rupees.”
Dilawar says Karachi fire fighters have been working through the night and have called for assistance from firefighters from Hyderabad, a Pakistani city 140 kilometers north of Karachi.
Experts suggest that the attack is an effort by Taliban-linked Sunni extremist groups to foment sectarian conflict between Pakistani's majority Sunni and minority Shi'ite Muslims.
Echoes Of 2007
The attack has left Karachi residents, who fear a return of instability in a city that suffered numerous ethnic riots and military operations in the 1980s and 1990s, searching for answers.
Since the Pakistani government launched a military operation in the country's western tribal areas in mid-October, the Pakistani Taliban has responded with major attacks in the northwestern city of Peshawar, the garrison city of Rawalpindi, the adjacent capital Islamabad, and the eastern city of Lahore in Pakistan's eastern Punjabi heartland.
But before the December 28 attack, Karachi had been spared.
The last major terrorist attack in Karachi took place in October 2007, when some 140 people died in bomb attack on the motorcade of former Pakistani Prime Minister Benazir Bhutto as she returned home from years in exile.
Nausheen Wasi, who teaches international relations at Karachi University, recalls a terrorist attack that took place in Karachi in April2006 to help explain why the city may have been targeted.
Wasi says that the 2006 suicide attack wiped out the top leadership of a Sunni religious organization. She believes the attack on the Shi'ite procession may have been intended to foment a sectarian war.
"Basically the target was chosen to exploit the situation in the city so it might be given a sectarian color," she says. "But people have become very mature; they understand the motives of those attacks. And I see a very mature response from all the political parties and from all the sectarian leadership. That's a very good sign despite all the panic around."
Military Leaders’ Legacy
Iqbal Haider, a Karachi resident who heads the Human Rights Commission of Pakistan, tells RFE/RL that a "frightening and deafening silence" engulfed Karachi today.
Haider, whose organization has won international praise for its outspoken criticism of extremism and human rights violations in Pakistan, rejected the notion that the bombing was part of a new militant campaign in a city whose overcrowded neighborhoods are reputed to provide sanctuaries to fugitive extremist leaders.
"The fact is that Karachi always had a huge number of madrassahs giving training to these militants. We have witnessed one of the bloodiest sectarian clashes," he said.
"If those clashes did not occur for two years, that does not mean that Karachi was a sanctuary for these terrorists. No sir, the whole of Pakistan is a sanctuary for these terrorists thanks to the ill-conceived policies of [former Pakistani presidents] General Pervez Musharraf and General Zia-ul-Haq," Haider said.
Like many Pakistanis, Haider blames Pakistan's erstwhile military rulers and their geostrategic policies for the country’s current suffering. He says that former military dictator General Muhammad Zia-ul-Haq's policy of arming and supporting anti-Soviet Afghan mujahedin rebels transformed Pakistani society and paved the way for Al-Qaeda to establish itself in the country.
Haider suggests that during his nine years in power, former President General Pervez Musharraf did little to contain militants, even as he publically backed the Western campaign against extremists.
Officials in Karachi are now faced with the prospect of confronting militant networks active in the metropolis.
They have previously claimed that the Pakistani Taliban generate considerable funding from crime rackets in the port city, which also serves as a transit route to the Gulf region.
Karachi residents, however, appear to have little patience for a complicated long-term struggle. They seek a quick solution that will allow them to resume their normal lives.
"What has happened is against humanity," said local resident Noorullah, echoing a sentiment common among Karachi residents.
"This should not have happened. This is harmful to our religion and our country,” Noorullah said. “This kind of thing is lowering our image in the world."