Pakistan says it has killed more than 100 militants in a security crackdown following Thursday's attack on a shrine that left at least 80 people dead.
A suicide bomber blew himself up among devotees at the Sufi shrine in the town of Sehwan.
Pakistan has reacted with raids across the country and by lashing out at Afghanistan which it accuses of tolerating militant sanctuaries.
So-called Islamic State said it had carried out the attack.
It was the latest in a string of bombings by the jihadist group.
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In response, some 18 militants were killed in southern Sindh province, where the Sufi shrine is located, and another 13 in the north-west, officials said. It is unclear where the other alleged terrorists were killed.
Border crossings with Afghanistan have been closed and rockets have been fired into two Afghan provinces.
Funerals for victims have been taking place on Friday and the Sindh provincial government has announced three days of mourning.
Some 250 people were also wounded in the attack.
Correspondents say crackdowns of this type are a regular response from the state following a major militant attack.
However the number of militants the army is claiming to have killed this time is higher than normal, says the BBC's M Ilyas Khan in Islamabad.
The military needs to offset the impression that it is losing the war against militants, he adds.
Earlier, the paramilitary Rangers said they had targeted militants overnight in Sindh, while police said further raids were carried out in Khyber Pakhtunkhwa in the north-west.
The army also summoned officials from the Afghan embassy to its headquarters in Rawalpindi, protesting that Afghan soil was being used as a base for militants to carry out attacks in Pakistan.
Devotees continued to flock to the shrine of Sufi saint Lal Shahbaz Qalandar in Sehwan on Friday.
The mood was defiant, with the customary naqqara (drum beating) taking place at daybreak as usual, and worshippers vowing to hold their routine dhamal (sacred dance) in the evening.
There were also angry scenes, with some worshippers complaining to police that they had not provided enough security despite previous threats to the shrine.
The shrine attack was the most deadly in a series of militant attacks since Sunday that have killed more than 100 people across Pakistan, including civilians, police and soldiers.
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