Four people have been arrested on suspicion of facilitating a suicide bombing that killed more than 30 people on Friday, Pakistan's interior minister has said.

Mohsin Naqvi stated that an Afghan national who is alleged to be the mastermind behind the attack was among the detained. One counter-terrorism officer was killed and three more were wounded during the raids that led to the arrests, he added.

The Islamic State group has claimed responsibility for the bombing that targeted Friday prayers at the Shia mosque in the Tarlai area, packed with worshippers at the time.

More than 160 individuals were injured in the blast, which constituted the deadliest incident in the capital for over a decade.

On Saturday, huge crowds gathered in Islamabad to mourn the 32 victims, with funeral prayers taking place under heavy security measures, including soldiers standing guard and police checkpoints in effect.

Prime Minister Shehbaz Sharif condemned the attack, expressing deep grief, while President Asif Ali Zardari denounced the targeting of innocent civilians as a crime against humanity. Eyewitnesses have recounted the chaos that ensued after the blast, describing the scene where bodies were strewn about.

Naqvi also accused India of funding those behind the attack and asserted that Pakistan would intensify security measures across Islamabad by recruiting thousands of new police officers and upgrading the city’s security systems.

This tragic assault follows a week of violence in Balochistan, where 58 civilians were slain in coordinated attacks linked to the Balochistan Liberation Army (BLA).