March 29, 2017 0310 GMT
The terror attack — Pakistan's deadliest in years — stunned the nation and raised questions about the authorities' ability to rein in terrorist groups despite several military offensives targeting terrorist hideouts, AP reported.
It also threatened to drive a deeper wedge between Pakistan and Afghanistan. Islamabad quickly lashed out at Kabul, saying the bombing was masterminded in militant sanctuaries across the border in Afghanistan.
Underscoring tensions, Pakistan fired a blistering round of artillery shells into Afghan territory on Friday and shut down the Torkham border crossing, a key commercial artery between the two neighbors.
Afghan President Ashraf Ghani condemned the shrine attack. "Sufis always preach peace and brotherhood among people," he said in a statement, adding added that "terrorists once again proved that they have no respect for Islamic values."
Meanwhile, raids overnight across Pakistan targeted terroirst hideouts and led to shootouts with insurgents that left at least 39 suspects dead, according to three Pakistani security officials.
In Thursday's attack, the suicide bomber walked into the main hall at the Lal Shahbaz Qalandar Shrine in Sehwan, and detonated his explosives among a crowd of worshippers, initially killing 75. At least 20 women and nine children were among the dead.
On Friday, authorities raised the death toll to 88 after some of the critically wounded died. The Sindh Provincial Health Department said a total of 343 people were wounded in the attack but that most were discharged after treatment while 76 still remain in hospitals.
The Sehwan shrine, which reveres a Muslim Sufi mystic, is frequented by the faithful of many sects of Islam but the majority of the worshippers are usually Shia Muslims.
Local TV showed graphic footage of the aftermath of the blast, with wounded worshippers crying out for help and the floors covered with shoes, blood and body parts. Women cried and beat their chests in grief.
Prime Minister Nawaz Sharif vowed that security forces would track down the perpetrators, according to Pakistani state TV.
"Each drop of the nation's blood shall be avenged, and avenged immediately," Pakistan's Army Chief, Gen. Qamar Javed Bajwa, said in a statement.
The attack was the deadliest in Pakistan after the Dec. 16, 2014 assault on an army-run school in Peshawar that killed 154 people, mostly schoolchildren. A Taliban-linked group, Jamaat-ul-Ahrar, claimed responsibility for that attack.