A suicide bomb attack on a hospital in the Afghan capital, Kabul, has left six people dead and 23 wounded.
The bomber detonated his device in a tent in the grounds of Charsad Bestar Hospital where medical students were eating lunch.
The hospital treats Afghan military personnel and is in a heavily fortified part of the city, yards from the US embassy and international forces HQ.
The Taliban said they had carried out the attack.
Eyewitness Mohammad Hakim, who was selling fruit from a cart near the hospital, said: "It was a big explosion. I fell to the ground."
There were fears that a second suicide bomber had got into the hospital, and staff were told to lock themselves in their rooms while soldiers searched the building, but no-one has been found.
'Ruthless and cowardly'
Defence ministry spokesman Gen Mohammad Zahir Azimi said the victims had all been civilians and medical students.
After the blast, relatives of hospital patients gathered nearby after trying to seek assurances that their family members were safe, AFP news agency reported.
President Hamid Karzai condemned the attack, saying that the perpetrators were "so ruthless and cowardly that, in contradiction of all humane and Islamic principles, they attack even hospital patients and doctors."
Only last month the Taliban announced the beginning of their Spring offensive against Afghan and international forces, and that came just after a suicide bomber made his way inside the Ministry of Defence.
Nato says it is making progress against the insurgents but the Taliban are still able to strike at the Afghan government even in its most heavily guarded bases, says the BBC's Quentin Sommerville, at the scene.
The 400-bed Charsad Bestar Hospital was built in the 1970s. It treated soldiers wounded during the Soviet occupation, people injured in the civil war that followed their retreat and, more recently, senior Taliban and al-Qaeda commanders.
After the fall of the Taliban, Western countries invested millions of dollars in the hospital, upgrading its facilities and installing state-of-the-art medical equipment and supplying air ambulances.