Air strikes on a hospital in the Afghan city of Kunduz that killed 19 people were "tragic, inexcusable and possibly even criminal", the UN human rights chief says.

High Commissioner Zeid Ra'ad Al Hussein urged a full and transparent investigation into the attack.

Medical charity Medecins Sans Frontieres said at least 12 of its staff and seven patients were killed.

US forces were carrying out air strikes at the time.

At least 37 people were seriously injured, 19 of them MSF staff.

"All indications currently point to the bombing being carried out by international Coalition forces," MSF said.

The Nato alliance has admitted its forces may have hit the hospital.

High Commissioner Zeid said: "International and Afghan military planners have an obligation to respect and protect civilians at all times, and medical facilities and personnel are the object of a special protection.

"These obligations apply no matter whose air force is involved, and irrespective of the location."

BBC