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 said an Afghan national who is alleged to be the mastermind behind the attack was among those detained. One counter-terrorism officer was killed and three more were wounded in the raids to arrest the suspects, he added. The Islamic State group has claimed responsibility for the bombing that targeted Friday prayers at the Shia mosque in the Tarlai area, when it was packed with worshippers. More than 160 people were injured in the blast, which was the deadliest in the capital for more than a decade.

Huge crowds were seen in the city on Saturday, as thousands of mourners gathered for the funerals of the bombing's 32 victims. Funeral prayers took place amid tightened security, with soldiers standing guard and police checkpoints set up in key areas. Ashiq Hussain, who lost his 21-year-old nephew Mujtaba Ali in the attack, told the Reuters news agency his family was 'broken'.

Condemning the attack on Friday, Pakistan's Prime Minister Shehbaz Sharif expressed 'deep grief'. The country's President, Asif Ali Zardari, said 'targeting innocent civilians is a crime against humanity'. Eyewitnesses and survivors of the blast have told the BBC how the attack unfolded, with some sharing harrowing details of the aftermath.

Naqvi accused India of funding those behind the attack and giving them targets, a claim rejected as 'baseless' by the Indian foreign ministry. Pakistani Defence Minister Khawaja Asif suggested that Afghanistan had a role in the bombing, a comment dismissed as 'regrettable' by the Afghan Taliban government. Naqvi has pledged to enhance security in Islamabad.

The explosion came after a week of violence in Balochistan province, leading to the deaths of 58 civilians in other coordinated attacks, which were claimed by the Balochistan Liberation Army.