KABUL, Afghanistan -- Officials say at least 32 civilians have been killed after a suicide bomber attacked a Shiite mosque in the Afghan capital, Kabul.

United Nations Assistance Mission in Afghanistan reported the death toll from the explosion, and said it also left more than 50 people wounded, many of them children. Earlier in the day, the Afghan authorities said at least 28 people were killed and 48 wounded.

A wounded Afghan boy receives treatment at the Estiqlal Hospital after a massive suicide blast at a Shiite mosque in Kabul, Nov. 21,2016. Getty

The Interior Ministry of Afghanistan confirmed in a statement that a suicide attack had taken place inside the Baqir-ul Ulom mosque in western Kabul.

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Faredoon Obiadi, head of the criminal investigation department for the Kabul police, said the attacker was on foot and detonated his suicide vest among the crowds inside the mosque.

The attack took place on the first floor of the two-story building where Shiite worshippers had gathered to commemorate the death of Imam Hussein, the Prophet Muhammad’s grandson and an iconic Shiite martyr, in Karbala, Iraq in 680 A.D.

“I was inside the mosque and the Mullah was reading the prayer, suddenly a huge explosion happened then everywhere was dark,” said Ewaz Ali, 50 who suffered minor injuries.

Afghans are seen inside the Baqir-ul Ulom mosque after a suicide attack, in Kabul, Afghanistan, Nov. 21, 2016. AP

CBS News’ Ahmad Mukhtar reports Taliban spokesman Zabihullah Mujahid denied in a statement that the group had anything to do with the attack.

The Islamic State of Iraq and Syria (ISIS) claimed responsibility later Monday via its own news agency, Amaq. The militant group has been blamed for previous attacks targeting minority Shiites in Kabul.

CBS News correspondent Charlie D’Agata says video of the aftermath of the attack fails to impart the devastation wrought by the bomber, but photos from inside the building -- too graphic to show -- reveal bodies torn apart by the force of the blast. Several children’s bodies are seen among the victims.