Pakistan's political and military leaders on Friday said they would go to any length to crush extremists after more than 100 people were killed in a latest wave of violence this week ending a period of fragile calm.
A spate of suicide bombings, improvised explosive device explosions and drive-by shootings claimed by Taliban insurgents and Islamic State militants shook the country this week.
An Islamic State suicide bomber blew himself among devotees at the
most revered shrine of Sufi Islam overnight Thursday, killing 70 people and culminating the deadliest week in several months.
The death toll rose to 75 on Friday, said Moin Ahmed, a doctor at a local hospital in Sehwan Sharif in the southern province of Sindh.
Nearly 50 of 250 people wounded in the attack remained in a critical condition, which means more deaths were expected, Ahmed added.
Prime Minister Nawaz Sharif condemned the massacre as an attack on the future of "progressive, inclusive" Pakistan and vowed to do "anything possible" to protect the country, his office said.
Military chief Qamar Bajwa vowed to step up ongoing offensives against Taliban rebels, saying every drop of blood would be avenged.
Violence has declined in Pakistan since the army pushed back the Taliban from their hideouts in the tribal regions near the Afghan border in a series of operations which started in mid-2014.
The surge this week appears a fresh challenge for security forces and a reminder that insurgents are still a threat.
Sindh province has begun three days of official mourning for the victims of the shrine bombing and the burials are expected to start later on Friday, local official Munawar Mehsar said.
Pakistani devotees stand on the blood-stained floor a day after a bomb attack hit the 13th century Sufi shrine of Lal Shahbaz Qalandar in the town of Sehwan in Sindh province, on Friday.
Men and local religious leaders chant slogans as they protest to condemn Thursday\'s suicide blast
Relatives gather to attend funeral prayers for bombing victims in Sehwan Sharif in Sindh province
Men comfort each other as they attend the funeral of a relative on Friday
Policemen gather outside the tomb of Sufi saint Syed Usman Marwandi in Sehwan Sharif on Friday
Men comfort each other during the funeral of a relative who was killed in a suicide blast
A man mourns the death of a relative who was killed at the tomb of Sufi saint Syed Usman Marwandi
Pakistani security officials inspect the blood-stained floor after a bomb attack hit the Sufi shrine
A Pakistani security official collects evidence a day after the suicide blast at the shrine
