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, alleged to be the mastermind behind the attack, was among those detained. During the raids to arrest the suspects, one counter-terrorism officer was killed, and three others were injured.

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

More than 160 people were reported injured in the blast, marking the deadliest attack in the capital in over a decade. In response to the attack, thousands gathered in Islamabad to mourn the 32 victims on Saturday, with funeral prayers being conducted under tight security.

Pakistan's Prime Minister Shehbaz Sharif expressed profound sadness over the tragedy, while President Asif Ali Zardari condemned the targeting of innocent civilians as a serious crime against humanity.

Eyewitnesses described the chaos after the explosion, with some expressing disbelief at the sight of casualties. Amid these violent events, Naqvi accused India of funding those involved in the attack, which India has firmly rejected, deeming the accusations as baseless.

Pakistan's Defense Minister suggested potential involvement from Afghanistan, prompting the Afghan Taliban to label the comments regrettable and unfounded.

In the wake of the attack, authorities pledged increased security measures across Islamabad, including plans to hire thousands of additional police officers.

Despite Islamabad being relatively secure compared to other regions, this incident follows a week of violence in Balochistan province that left 58 civilians dead, attributed to the Balochistan Liberation Army (BLA) militant group.