Five people have been killed and 66 injured after gunmen dressed as doctors attacked the Sardar Mohammad Daud Khan military hospital in Kabul on Wednesday morning. The attack has been claimed by the Islamic State terrorist group, also known as ISIS.

The number of casualties may go up, since the exchange of gunfire between the militants and the Afghan security forces has been going on since the morning, according to Pajhwok Afghan News. ISIS claimed to have killed over 100 people, according to local sources who also reported sources in the army putting the number of dead at 30, but those numbers have not been officially verified.

President Ashraf Ghani condemned the attack on the hospital, saying it "trampled all human values."

"In all religions, a hospital is regarded as an immune site and attacking it is attacking the whole of Afghanistan," he told BBC.

MG Dawlat Waziri, spokesman for the country's Ministry Of Defense said in a press release: "Today around 9:00 a.m. (11:30 p.m. EST Tuesday), a number of insurgents entered to [sic] Sardar Muhammad Dawood Khan’s 400-bed Hospital using medical staff’s uniform. Clashes between terrorist and Security forces are ongoing, backup forces sent to suppress enemies. National Ministry of Defense assures people that brave ANA soldiers will kill these terrorists at soonest."

Abdul Qadir, a worker at the military hospital told Reuters he noticed a gunman disguised in a doctor's white coat and saw him take out a concealed AK-47 assault rifle. The gunman opened fire, killing at least one hospital worker and one patient. He said he also heard firing from several other places inside the hospital, which is situated only a few hundred meters away from the diplomatic quarter of Kabul, which also houses the U.S. embassy.

Afghan Chief Executive Abdullah Abdullah also condemned the attack.

The U.S. embassy in Afghanistan also condemned the attack, saying it demonstrated a "blatant disregard for human life by those seeking to disrupt Afghanistan’s democratic progress."

The injured were taken to the Wazir Akbar Khan hospital, according to Smael Kawosi, media relation officer for the Ministry of Health, who spoke to CNN.

"At first there was a firing followed by a huge blast," an employee at the nearby hospital told CNN.