The deadly blunder that killed 70 civilians in an air strike - ordered by a German commander and carried out by the US Air Force - shows an urgent need for unity of command.
Meanwhile a British journalist who was abducted by militants in Afghanistan has been freed by British troops.
His Afghan translator and three others were killed during the rescue mission.
Stephen Farrell, a reporter for the New York Times, was kidnapped on Saturday while he was covering the aftermath of the air strike on two NATO fuel tankers hijacked by the Taliban.