Six people have died in a major explosion at the main Afghan military hospital in Kabul.
The defence ministry said there had been a blast in a tent at the hospital.
A number of others have been wounded. Casualties included civilians and military personnel.
Afghanistan's Tolo television station said the blast was caused by a suicide attack.
Tolo reported the blast took place as medical students were having lunch.
A Western military source also said there had been shooting inside the compound. The claim could not be independently verified.
Roads to the hospital have been blocked as Afghan security forces cordoned off the facility, while police and soldiers are also on the scene.
Relatives of patients inside the hospital gathered nearby after trying but failing to find out if their family members are safe, an AFP reporter at the scene said.
There has been a recent spike in suicide bombings - a key Taliban tactic - and other attacks in Afghanistan.
Two rockets were fired overnight into Kabul city landing in an empty plot, causing no damage or casualties, interior ministry spokesman Zemarai Bashary said.
Afghan forces are set to take increasing responsibility for security as foreign troops pull back.
The worst fighting in Afghanistan usually comes in spring and summer and the fighting season is starting to get under way.
The Taliban announced the start of its spring fighting season at the end of last month.
On Thursday, 36 people were killed when they attacked a road construction company's compound in eastern Afghanistan.
There are around 130,000 international troops in Afghanistan fighting the Taliban and other insurgents.
The conflict started with the US-led invasion of Afghanistan in 2001 following the 11 September attacks and has now run for nearly ten years.
