Afghan experts probe site of deadly Kabul hospital attack

Injured men lie on bed at a hospital after the Wednesday's attack and shooting at a military hospital in Kabul, Afghanistan, Thursday, March 9, 2017. Gunmen wearing white lab coats stormed a military hospital Wednesday, killing dozens of people and wounding dozens in an attack claimed by the Islamic State group. (AP Photo/Rahmat Gul) (The Associated Press)

An Afghan soldier stands guard at a military hospital after an attack in Kabul, Afghanistan, Wednesday, March 8, 2017. Afghanistan’s Defense Ministry said more than 30 people have been killed in this morning’s attack on the military hospital in Kabul. An affiliate of the Islamic State group is claiming responsibility for the attack, which happened in Kabul’s heavily guarded diplomatic quarter. (AP Photo/Rahmat Gul) (The Associated Press)

An Injured man receives treatment at a hospital after the Wednesday's attack at a military hospital in Kabul, Afghanistan, Thursday, March 9, 2017. Gunmen wearing white lab coats stormed a military hospital in Afghanistan's capital on Wednesday, killing dozens of people in an attack claimed by the Islamic State group. (AP Photo/Rahmat Gul) (The Associated Press)

Afghans are mourning as funerals are underway following the deadly attack on a Kabul hospital the previous day that was claimed by the Islamic State group.

The death toll from the brazen daytime assault, which saw four gunmen in white lab coats storm the hospital, rose to 31 on Thursday after one of the wounded died overnight.

Defense ministry spokesman Mohammed Rodmanesh says experts are scouring every inch of the hospital, badly damaged after the hours-long attack on Wednesday, for evidence of the IS claim.

The attack also left 53 wounded.

Rodmanesh says that despite the IS claim, Afghan authorities "must do our own investigations to know who is responsible."

Afghan forces have been under increasing pressure by the Taliban and also from Islamic State militants, mostly in country's east.