A US soldier in Afghanistan has killed at least 16 civilians and wounded five after entering their homes in Kandahar province, senior local officials say.
He left his military base in the early hours of the morning and opened fire in at least two homes; women and children were among the dead.
Nato said it was investigating the “deeply regrettable incident”.
Anti-US sentiment is already high in Afghanistan after US soldiers burnt copies of the Koran last month.
US officials have apologised repeatedly for the incident at a Nato base in Kabul, but they failed to quell a series of protests and attacks that killed at least 30 people and six US troops.
Not good. Not good at all.