The commander of foreign troops in Afghanistan, US General Stanley McChrystal, has recorded a public apology to the Afghan people after a NATO air strike killed 27 civilians, the alliance said Tuesday. Foreign troops called in the attack on three vehicles in central Daykundi province on Sunday, thinking they were carrying armed militants towards their base, NATO said. The Afghan government said four women and a child were among 27 civilians killed, in the third such mistaken bombing raid in Afghanistan in a week.