BBC: More than 20 people have been killed and at least 16 injured in an attack on a military hospital in the Afghan capital Kabul, an official at the Ministry of Public Health told the BBC.
A Taliban spokesman confirmed there had been two explosions – the first in front of the 400-bed Sardar Daud Khan hospital and the second nearby.
Gunmen then broke into the hospital grounds, witnesses said.
No-one immediately claimed responsibility for the attack.
The Taliban spokesman, Bilal Karimi, told the BBC that fighters from the Islamic State affiliate IS-K had entered the compound after detonating the first explosion at the entrance gate.
Mr Karimi said Taliban fighters shot and killed four IS-K attackers and captured one alive.
Photographs and video footage from Kabul showed a plume of smoke over the area and recorded the sounds of gunfire. A doctor in the building told the AFP news agency he had been sent to seek shelter in a safe room during the attack and could hear guns being fired.
The attack is the latest to hit Afghanistan since the Taliban seized control in August, after the US withdrew its last troops from the country. IS-K, which stands for Islamic State Khorasan, has claimed responsibility for a number of attacks targeting civilians and Taliban fighters.
A bombing by the group at Kabul international airport in August killed more than 150 civilians and 13 US soldiers.
The Sardar Daud Khan hospital has been targeted before. More than 30 people were killed and 50 others wounded in 2017 when gunmen dressed as doctors stormed the building. That attack was also claimed by the Islamic State group.