Moments after a devastating bombing at Lal Shahbaz Qalander shrine in Sehwan, Sindh, the Pakistan military issued a strongly worded statement to "hostile powers", saying it will respond to such attacks.

In a short message posted to Twitter, Director General Inter-Services Public Relations (DG ISPR) Maj Gen Asif Ghafoor said, "Recent terrorist acts are being executed on directions from hostile powers and from sanctuaries in Afghanistan. We shall defend and respond."

"Each drop of the nation's blood shall be revenged, and revenged immediately. No more restraint for anyone," the army chief was quoted as saying.

He added that Chief of Army Staff Gen Qamar Javed Bajwa has appealed for "calm".

"Your security forces shall not allow hostile powers to succeed. We stand for our nation," Ghafoor quoted COAS Bajwa as saying.

At least 80 people were killed and scores injured in a suicide attack on the shrine of Lal Shahbaz Qalandar in Sehwan on Thursday evening. The attack is the fourth in a string of a shocking wave of militancy across the country, with Lahore, Quetta and Mohmand Agency struck in the last four days.

PM condemns attack

Prime Minister Nawaz Sharif said that an attack on the shrine of Lal Shahbaz Qalandar is an attack on the progressive and inclusive future of Pakistan.

"The Sufi people predate Pakistan's history, and played an important part in the struggle for its formation," he said.

"An attack on them is a direct threat to Jinnah's Pakistan and will be dealt as such," the PM was quoted as saying in a statement released by his media office in Islamabad.

Sindh Governor Mohammad Zubair, in his message of solidairty, said, "Sindh is a land of the Sufis. The terrorists have targeted the devotees to achieve their nefarious designs."

"This attack tantamounts to attack on the entire nation."