KABUL: Grieving worshippers Wednesday described desperately trying to shelter their children against a hail of gunfire in Kabul that killed at least 18 people gathering to mark Ashura, one of the most important festivals of the Shiite calendar.

According to witnesses, gunmen entered the Karte Sakhi shrine near Kabul University late Tuesday, firing “indiscriminately” on men, women and children as they tried to flee.

The UN in Afghanistan called the attack an “atrocity” and put the toll at 18 on Wednesday.

But the interior ministry later said in a statement that 16 people including three women and two children were killed and 54 wounded in two separate attacks in Kabul Tuesday night.

The statement said the shrine was attacked by an armed suicide bomber wearing a military uniform and apparently acting alone, who started spraying bullets at worshippers.

At the same time, another attacker entered a nearby mosque and took an unspecified number of people hostage as they were commemorating Ashura.

Both attackers were killed by Afghan security forces and the hostages were released, the statement said, without clarifying if any casualties were sustained in the second assault.

In a Kabul hospital on Wednesday, victims wounded in the attack on the shrine said more than one gunman was involved in the attack.

The UN released a statement saying: “This attack deliberately targeting a large group of civilians exercising their right to freely manifest their religion in worship, observance and practice is an atrocity.”

The Taliban said they were not involved and no group has yet officially claimed responsibility for what President Ashraf Ghani condemned as a “clear sign of a crime against humanity”.