A powerful explosion ripped through a crowd of Shiites as they left a mosque in Karachi, Pakistan’s largest city, on Sunday, killing at least 45 people. It was the latest atrocity in an escalating campaign of countrywide sectarian violence.
No one immediately claimed responsibility for the blast, which badly damaged two apartment blocks and spread fire through homes and shops. At least 149 people were wounded, city officials said.
But suspicion fell heaviest on Lashkar-e-Jhangvi, a Sunni militant group at the forefront of a wave of violence against Shiites that has killed about 200 people so far this year, and which is rapidly emerging as a substantial threat to Pakistan’s internal security.
“This is terrorism at its worst,” said Sardar Mehdi Musa, a leader of the Hazara Shiite minority, which has borne the brunt of recent violence. “It’s a sign that things are only going to get worse.”
Last last month, the authorities in Punjab Province detained the Lashkar leader, Malik Ishaq, but as Sunday’s violence in Karachi suggests, it seems unlikely that his detention will halt sectarian attacks.
In Karachi, rescue workers scrambled to find survivors amid scenes of striking devastation after the bombing in Abbas Town, a majority Shiite neighborhood. Early police reports suggested that the blast had been caused by a car bomb and that a second, smaller explosion might have been caused by the ignition of domestic gas canisters.
Fire spread through homes and shops; many women and children were among the dead, hospital officials said. Fayaz Leghari, the police chief of Sindh Province, said the police had intercepted explosive-laden vehicles in the previous two weeks after receiving warnings of an impending attack. But they did not have specific intelligence about Sunday’s attack, he said.
President Asif Ali Zardari and Prime Minister Raja Pervez Ashraf, who was visiting Karachi at the time of the blasts, condemned the attack. Mr. Ashraf said that those who attacked civilians were “serving the interests of antistate and antisocial elements,” according to the state-run news agency, The Associated Press of Pakistan.
It was the latest salvo in an alarming surge in sectarian violence across Pakistan over the past year, from attacks on travelers in the remote northern mountains to bombings in the tribal belt and Karachi, a sprawling and volatile metropolis already reeling from political, ethnic and criminal killings.
The worst attacks have occurred in Quetta, the capital of Baluchistan Province, where two bombings by Lashkar-e-Jhangvi militants in January and February killed almost 200 Shiites from the ethnic Hazara minority. Mr. Musa, the Hazara leader, said that another member of his community was shot and killed Saturday on a Karachi street.
“It was definitely a targeted killing,” he said. “Why else would they kill a poor Hazara man?”
Shiite protests against the violence have been largely peaceful until now, although experts on Pakistan’s militants fear that may change if the attacks continue. On Sunday night, Shiites in Karachi fired their weapons into the air to protest the killings.
During an all-parties political conference in Islamabad last week, Shiite leaders walked out in protest when Maulana Muhammad Ahmed Ludhianvi, the leader of a Sunni extremist political party, addressed the session.
Although the army has carried out sweeping military operations against the Pakistani Taliban since 2009, it has avoided a full-frontal confrontation with the country’s sectarian groups. In some parts of the country, the military and conservative political parties have faced accusations of collusion with sectarian groups.
The most attention has been focused on Mr. Ishaq’s group, Lashkar-e-Jhangvi. Interior Minister Rehman Malik said last week that it was involved in 80 percent of the militant attacks in Pakistan. That figure may be an exaggeration but, with elections expected to be held by mid-May, few doubt that the sectarian violence could be politically destabilizing.
Analysts say that instability in Karachi, a city that includes a sizable Shiite minority among its population of least 18 million people, could delay the elections. During Pakistan’s last sustained bout of sectarian violence, in the 1990s, the streets of Karachi became a proxy battleground between Sunni militant groups supported by Saudi Arabia and Shiite groups that had assistance from Iran.
The coalition government, led by the Pakistan People’s Party, is expected to step down by March 16, marking the first time a civilian government will have served a full five-year term. But the deteriorating security situation has raised questions about its use of resources.
Local news media reported that a contingent of the Karachi police officers had been deployed to protocol and security duties at the engagement ceremony of Sharmila Faruqui, a provincial minister from the governing party, and Hasham Riaz Sheikh, an aide to President Zardari.