KARACHI: Business and educational institutions in Karachi and other cities of Sindh were shut on Friday, for the second time in a week, a day after six people were killed and 12 others injured in a blast targeting an election office of the Muttahida Qaumi Movement (MQM).

Schools, businesses, shops and petrol stations were closed in the city and public transport was scarce.

Thursday’s explosion damaged buildings and vehicles in the city’s Nusrat Bhutto Colony. The dead and injured were shifted to the Abbasi Shaheed Hospital. Sources said three brothers were among the six deceased.

MQM spokesman Qamar Mansur said the office was closed following a bomb blast on Tuesday at the People’s Chowrangi in North Nazimabad.

All the victims of Thursday’s blast were standing outside the office when the bomb exploded, Mansur said.

Subsequently, the MQM announced a day of mourning across Sindh on Friday.

The proscribed Tehrik-i-Taliban Pakistan (TTP) claimed responsibility for the attack.

Speaking to Dawn.com on telephone from an unspecified location, TTP spokesman Ehsanullah Ehsan said his organisation had targeted the MQM as it had vowed to do so.

The TTP had previously threatened to attack the Pakistan Peoples Party, Awami National Party and MQM.

But MQM spokesman Wasay Jalil expressed his party’s resolve of not leaving the ground and to take part in the May 11 elections.

Moreover, chief of the MQM Altaf Hussain appealed to all citizens of Pakistan to take every possible precaution to ward off any incident of terrorism.

Addressing the party’s Rabita Committee along with law enforcement officials and members of various organisations, Altaf said that state institutions had failed in their duty to provide security to the citizens.

He said that people residing in the urban areas should immediately inform the police about suspicious persons, vehicles and objects to save themselves from any potential threat of a terrorist attack.

Altaf expressed grief and condolences over the bombing of MQM’s election office in Karachi’s Nusrat Bhutto Colony.

He advised citizens to be alert at all times and report unsettling incidents to the police.

Meanwhile, Governor Sindh Dr Ishratul Ibad ordered a swift probe report of the incident from the authorities concerned.

In yet another terror attack, unknown gunmen opened fire on a Rangers post in Sindh’s second largest city, Hyderabad. A Rangers sepoy died in the attack.