Police say at least 194 people were injured inside a Shiite Muslim mosque in Peshawar, a city in the northwestern part of the country. The Islamic State Khorasan, or ISIS-K, later claimed responsibility for the attack, according to a translation of an ISIS statement by the SITE Intelligence Group, the New York Times reported.

In recent months, the country has experienced an increase in attacks and violence. Friday’s bombing was one of the deadliest incidents in Peshawar, which has a population of approximately 2 million people near the border of Afghanistan.

The violence started when an armed attacker on a motorbike opened fire at police outside the mosque, killing one officer and injuring another. The suicide bomber had strapped a device with 12 pounds of explosives to his body before entering the mosque and detonating the vest, AP reported.

Ambulances rushed through the narrow streets to reach the scene, while several people covered in blood were seen getting carried out on stretchers. The majority of people who were injured were taken to Lady Reading Hospital for treatment. The hospital’s spokesman Asim Khan said numerous people were struck or injured by shrapnel and flying debris. Multiple people also had limbs amputated due to the injuries sustained from the attack, AP reported.

CCTV footage of the bombing showed the attacker wearing a large black shawl that covered most of his body, shielding the device from view. The attacker was seen rapidly moving up the narrow street before firing at police stationed outside of the mosque who were there to protect it. The attacker proceeded to enter the mosque and detonated the device, AP reported.

Moazzam Jah Ansari, a top police official, said the bomb was filled with ball bearings, a method used to create the most carnage in an attack. Devices containing ball bearings are used to disperse deadly projectiles in a larger area, which is why the death toll in this attack was so high, he said according to AP.

Police have recovered empty bullet cartridges, pallets and pieces of the gun used in the initial attack outside the mosque, Peshawar police chief Muhammed Ejaz Khan said according to the Times.

Last fall, the ISIS-K had carried out two bombings at different Shiite mosques in Afghanistan, resulting in the deaths and injuries of dozens of people. However, the mosque bombing on Friday was its deadliest and largest attack yet, according to the Times.