At least 33 citizens, including many students, were killed in a bombing at a mosque and religious school in the Imam Saheb town of the Kunduz province in northern Afghanistan on Friday, the Associated Press reported.

The bombing that took place during the Friday prayers, also injured 43 devotees, according to Zabihullah Mujahid, the deputy culture and information minister of the Taliban administration in Afghanistan.

The blast took place just a day after a series of bombings in Afghanistan, that killed at least 15 citizens, including 12 who died in the blast at a Shiite mosque in the city of Mazar-e-Sharif. Afghanistan’s Islamic State affiliate known as Islamic State in Khorasan Province, or IS-K, had claimed responsibility for Thursday’s blasts.

The Shiite community, which is a religious minority in Afghanistan, is frequently targeted by Sunni militant groups, including the Islamic State.

Friday’s explosion was among the biggest attacks since the Taliban assumed power in Afghanistan in August. It was not clear how the bomb was detonated, an intelligence official told AFP on conditions of anonymity.

“The sight at the mosque was horrifying,” said Mohammad Esah, a shopkeeper told the news agency. “All those who were worshipping inside the mosque were either injured or killed.”

About a dozen ambulances took the wounded to the provincial hospital in Kunduz city.

UN secretary general’s Deputy Special Representative to Afghanistan, Ramiz Alakbarov, condemned the attacks on Friday, asking for perpetrators to be brought to justice.

“The indiscriminate use of improvised explosive devices, which has already caused more than 100 civilian casualties this week, is unacceptable and must cease immediately,” Alakbarov said on Friday.

The explosions on Thursday came two days after another series of blasts had hit Kabul on April 19. At least six citizens were killed in three explosions at the Abdul Rahim Shahid High School in the western part of the city.