Nato helicopters on Tuesday once again violated Pakistan airspace in the FATA region. Sources said that the helicopters had entered up to 600 metres inside Pakistan, including the areas of Borki, Kharlaki and Kurram and hovered in Pakistan airspace for 20 minutes. Nato helicopters had earlier twice violated airspace, including one violation which led to the killing of three Pakistani security personnel. Pakistan had closed the border with Afghanistan after the incident, halting Nato supplies going through the country.