Pakistan Prime Minister Imran Khan on Saturday demanded an immediate report on the Quetta mosque blast during Friday prayers that killed at least 15 people and left 20 others injured in the restive Balochistan province, terming the incident as a condemnable "cowardly terrorist attack".
The deadly blast came three days after a bomb explosion claimed two lives in Quetta.
Reacting to the incident, Prime Minister Khan condemned the explosion and demanded a report.
"I have demanded an immediate report on the condemnable cowardly terrorist attack in Quetta targeting a mosque & people at prayers. Have asked govt to ensure all medical facilities are provided to the injured. Martyred DSP Haji Amanullah was a brave & exemplary officer," he said on Twitter.
Khan said the best possible treatment would be given to the injured.
The nature of the explosion, which occurred inside the mosque during Maghrib prayers in Ghousabad neighbourhood, was not known.
Deputy Superintendent of Police (DSP) Amanullah was among the 15 people killed in the incident, Quetta Deputy Inspector General (DIG) Abdul Razzaq Cheema said.
According to some media reports, the slain police officer was the likely target. Last month, unidentified gunmen killed the DSP's son in Quetta, The Express Tribune reported. Twenty others were also injured in the blast, the report said.
Law enforcement agencies have cordoned off the area to investigate the incident.
The mosque, which is located in a densely-populated Pashtun-majority area, was being searched by the bomb disposal squad and security personnel.
The TV footage showed debris and shattered glass spread on the floor of the mosque.
No one immediately claimed responsibility for the blast.
Pakistan military's media wing ISPR said that troops of the Frontier Corps (FC) Balochistan have reached the site and were carrying out joint search operations with the police.
"Every possible assistance be given to police & civil administration. Those who targeted innocents in a mosque can never be true Muslim," the ISPR quoted army chief General Qamar Bajwa as saying.
Balochistan Chief Minister Jam Kamal Khan condemned the incident and expressed grief at the loss of lives.
Reacting to the incident, Balochistan Home Minister Zia Langove condemned it, saying "terrorists were scared of Pakistan's development".
"Internal and external enemies are making failed efforts to create panic and unrest in the country," he said in a statement.
He said that "defeated terrorists will never be allowed to succeed".
Talking about the casualties in the incident, Langove said the death toll might rise as the condition of some of the injured was critical after they were shifted to the Civil Hospital for treatment.
The blast occurred three days after two men were killed and over a dozen injured in a blast near a vehicle of the security forces in Quetta.