SHIKARPUR: At least 60 people were killed and 60 others injured in an explosion inside a central imambargah (mosque affiliated with Shia Muslims) in Sindh province's Shikarpur district on Friday.

Civil Hospital Shikarpur had issued a list of 49 victims out of whom 46 bodies had been identified whereas the identity of 3 others was yet to be confirmed.

The cause of the blast has not been ascertained, but suspicions are that it may have been the result of a suicide attack.

Reuters reported that Jundullah, a splinter group of Tehreek-i-Taliban Pakistan (TTP), which last year pledged support for the Islamic State group based in Syria and Iraq, claimed responsibility.

“Our target was the Shia mosque ... They are our enemies,” said Jundullah spokesman Fahad Marwat.

The Majlis Wahdatul Muslimeen (MWM) announced to observe a 'peaceful strike' across Sindh in the wake of the terrorist attack.

The Muttahida Qaumi Movement (MQM) have also given their support to the MWM's call for a day of mourning.

Sindh Chief Minister Qaim Ali Shah also announced a day of mourning for the victims of the blast.

The imambargah is located in Shikarpur's Lakhi Dar area and the explosion occurred just after Friday prayers.

A number of victims were trapped under debris after the roof of the imambargah collapsed due to the intensity of the blast. Many of the casualties were shifted to hospitals in Sukkur and Larkana districts of Sindh.

MWM central leader Allama Mohammed Amin Shaheedi announced three days mourning, describing the incident a failure of the government.

He told Dawn that the party's further course of action would be announced in a press conference later in the evening.

The Jafria Disaster Cell (JDC) demanded that the critically wounded victims be immediately shifted to Karachi for treatment.

A huge contingent of police, rangers and ambulances arrived at the scene from the nearby towns in the aftermath of the explosion.

Local resident Mohammad Jehangir told AFP he had “felt the earth move beneath my feet” as he prayed at another mosque around 1.5 kilometres away.

An official with a national Shia organisation, Rahat Kazmi, told AFP that up to 400 people were worshiping in the mosque when the blast struck.

Sindh Information Minister Sharjeel Inam Memon told Dawn that an emergency had been imposed at all hospitals in Shikarpur and surrounding talukas and cities.

He added that provincial Chief Minister Syed Qaim Ali Shah and Sindh Health Minister Jam Mehtab Dahar have taken strong notice of the incident.

Prime Minister Nawaz Sharif, President Mamnoon Hussain, Pakistan Tehreek-i-Insaf chairman Imran Khan and MQM chief Altaf Hussain issued condemnation messages against the incident.

Later Sindh Chief Minister Qaim Ali Shah visited the site of the explosion and announced Rs2 million compensation for the families of those killed.

Shah also announced Rs200,000 for each person wounded in the attack. He said the Sindh government would bear all medical expenses for the treatment of the injured.

Meanwhile 14 severely injured were shifted to a private hospital in Karachi for medical treatment.

MWM also staged sit-ins at several spots, including MA Jinnah road, in Karachi to protest against the Shikarpur tragedy.

A large number of people, including children, women and senior citizens participated in the sit-ins at Five Star chawrangi, Shahrah-e-Pakistan, Abbas Town, Star Gate Shahrah-e-Faisal and Malir 15.

Molana Hassan Zafar of MWM has announced that protests would continue till the deceased are buried after funeral prayers.

PTI, PPP, MQM and ANP have also endorsed the peaceful strike, called by the MWM.

Read: After Peshawar, Rawalpindi mourns

The incident comes as Pakistan is attempting to implement the National Action Plan to combat and root out terrorism from the country, an initiative that was set in motion after the Dec 16 attack on Peshawar’s Army Public School in December 2014.

Also read: Militants in Punjab

It was the second major attack on an imambargah in the country since the beginning of 2015; the first being an attack on Rawalpindi’s Imambargah Aun Mohammad Rizvi in the garrison city’s Chatian Hatian area.

At the same time, Pakistani security forces are engaged in the North Waziristan and Khyber tribal regions — with the operation in Waziristan starting soon after a terrorist attack on Karachi's Jinnah International Airport and the theater of war expanding into Khyber.