Senior police officer Shabbir Sethar said from a local hospital that the death toll was likely to rise.
“At least 72 are dead and over 150 have been injured,” Sethar said by telephone.
The attack on Lal Shahbaz Qalandar shrine in the town of Sehwan Sharif is the largest of a wave of bombings to hit Pakistan this week as the Pakistani Taliban and other radical Islamist militants carry out threats of a new offensive.
Islamic State claimed responsibility for yesterday’s attack.
Sehwan Sharif shrine is in the southern province of Sindh, where thousands of men and women gather every Thursday night for Sufi dance and music, provincial government spokesman Maula Bux Chandio said.
Local media reported a suicide bomber blew himself up inside the main compound of the shrine, but there was no official word on the nature of the blast.
Sufi shrines often come under attack by the rebel Taliban.
Yesterday afternoon, a roadside bomb hit an army convoy, killing three soldiers in the southwestern province of Baluchistan, the military said in a statement.
No group claimed responsibility for that attack.
More than 50 people have been killed in Taliban attacks since the start of the week, a marked uptick in violence.
Violence had declined in Pakistan since the military pushed back the rebel Taliban, which is allied with Al Qaeda, from the regions on the Afghan border in a series of offensives launched from mid 2014.
But the insurgents’ ability to launch surprise attacks remains a challenge for security forces and intelligence agencies.
Meanwhile, Pakistani counter-terrorism police raided a militant hideout and killed six suspected members of a Taliban faction that has launched a new campaign of violence against the government, police said yesterday.
The Counter Terrorism Department in Punjab province said its officers surrounded a hideout of the Pakistani Taliban’s Jamaat-ur-Ahrar faction in the city of Multan late on Wednesday and ordered the suspects inside to surrender.
“But the terrorists started firing at the raiding party and threw explosives,” a spokesman for the department, who the unit does not identify for security reasons, said in a statement.
Six militants were killed while three or four escaped under cover of darkness, the department added.
Two hand grenades, two automatic rifles and two pistols were recovered.
The militant faction claimed responsibility for a suicide bomb attack near the Punjab provincial assembly in the city of Lahore on Monday that killed 13 people and wounded more than 80.
Jamaat-ur-Ahrar said the attack was the beginning of a new campaign of violence against the government, security forces, the judiciary and secular political parties.
Since then, militants have killed two bomb-disposal officers in the western city of Quetta and a suicide bomber blew himself up outside a government office near the northwestern city of Peshawar on Wednesday, killing five people.
Also on Wednesday, a suicide bomber on a motor bike attacked a group of judges in a van in Peshawar, killing their driver.
The attacks have underlined the threat militants pose to the government of Prime Minister Nawaz Sharif despite an army offensive launched in 2014 to push them out of their strongholds near the Afghan border.
Pakistan’s foreign office said it had summoned Syed Abdul Nasir Yousafi, deputy head of mission at Afghanistan’s embassy in Islamabad, on Wednesday to voice concern about Jamaat-ur-Ahrar “sanctuaries” in Afghanistan.
