A bomb explosion in an Afghanistan mosque has reportedly left nearly 50 people dead and over 100 others injured.

According to the Washington Post, the attack took place in the northeastern city of Kunduz on Friday, as Shiite Muslims were conducting noon prayers at the Sayed Abad mosque. Witnesses say an individual walked into the place of worship and immediately detonated his explosive vest. A Taliban spokesperson told the outlet at least 46 people killed and 143 were wounded in the blast.

“I saw more than 40 dead bodies lying around,” said a 60-year-old witness who asked to be only identified by his middle name Ghausuddin. “There was blood everywhere. In every family, one or two people were either injured or killed.”

The Post reports ISIS-K claimed responsibility for the suicide bombing, which occurred just days after the group reportedly orchestrated another suicide bombing outside a Kabul mosque last Sunday. The attack reportedly left at least two people dead.

Officials say the death toll for Friday’s blast is expected to rise throughout the day. As of press time, there were conflicting reports about the number of deaths and injuries. A couple of health officials told Reuters the death toll could be anywhere between 70 to 80, while a United Nations agency reported more than 100 people were likely killed.

If the estimates are correct, Friday’s explosion will reportedly mark the deadliest terrorist attack since the U.S. withdrew from Afghanistan back in August.