According to authorities, a massive explosion swept through a crowded mosque in the Afghan capital Kabul, killing 21 people.

Khalid Zadran, a police spokesman in Kabul, reported that an additional 33 persons were wounded.

The explosion occurred during evening prayers on Wednesday. The imam of the mosque is reportedly among the dead.

It is unknown who was responsible for the attack, which occurred a week after Islamic State (IS) terrorists killed a pro-Taliban imam in Kabul with a suicide bombing.

Kabul’s explosion site has been surrounded by security personnel.

Witnesses reported hearing a massive explosion that damaged the windows of adjacent structures.

“I witnessed so many people slaughtered, and even individuals dragged out of the windows of the mosque,” an eyewitness told the news agency Reuters.

Stefano Sozza, director of the medical charity Emergency, which operates the city’s primary hospital, told that his organization has already treated 35 patients, including children.

“Our surgeons worked through the night on patients requiring surgical assistance. The majority of the victim’s injuries were caused by the explosion, as evidenced by the presence of shell fragments and burns on their bodies.

He felt the explosion occurred within the mosque. “There was likely someone entering the mosque at prayer time, so it was likely crowded when [the attacker] detonated this body-burning improvised explosive device.

Mr. Sozza stated, “Therefore, all those who were near the assailant were essentially killed, while those who were further away sustained many injuries.”

The mosque was crowded, the bomb was strong, and it appears that another cleric was in the sights of the Islamic State, the Taliban’s most formidable foe.

In the previous month, three major religious leaders in Kabul and other locations were targeted for assassination.

Last week, it was Sheikh Rahimullah Haqqani, a known Taliban ally. This time, it is Amir Muhammad Kabuli, who is reported to be a moderate Sufi.

A social media video depicted a scene of carnage.

A religious student who was immediately outside the mosque told that he witnessed the dead and injured, including children attending evening prayers, strewn about inside.

IS is known for its vicious attacks on the Shia Hazara minority group. But their focus appears to be expanding just as the Taliban celebrate one year in power – a coup that closed one chapter of a long, brutal struggle but opened another.

These Islamist groups have long been divided along ideological and religious lines, with these divisions being exacerbated by fierce personal and political competition. IS despises the Taliban for its diplomatic engagement with the United States and other western powers in recent years. The Taliban do not share IS’s dedication to an austere Salafist doctrine, its global jihadi ambitions, or its most vicious tactics.