GLOBAL ECONOMY

NATO: Blast inside US base in Afghanistan caused casualties

  • Afghanistan's National Army soldiers guard, blocking the main road to the Bagram Airfield's main gate in Bagram, north of Kabul, Afghanistan, Saturday, Nov. 12, 2016. An explosion at a U.S. airfield in Afghanistan early Saturday killed four people, the head of international forces in the country said. (AP Photos/Massoud Hossaini)

    Afghanistan's National Army soldiers guard, blocking the main road to the Bagram Airfield's main gate in Bagram, north of Kabul, Afghanistan, Saturday, Nov. 12, 2016. An explosion at a U.S. airfield in Afghanistan early Saturday killed four people, the head of international forces in the country said. (AP Photos/Massoud Hossaini)  (The Associated Press)

  • Afghanistan's National Army and police soldiers guard, blocking the main road to the Bagram Airfield's main gate in Bagram, north of Kabul, Afghanistan, Saturday, Nov. 12, 2016. An explosion at the U.S. airfield early Saturday killed four people, the head of international forces in the country said. (AP Photos/Massoud Hossaini)

    Afghanistan's National Army and police soldiers guard, blocking the main road to the Bagram Airfield's main gate in Bagram, north of Kabul, Afghanistan, Saturday, Nov. 12, 2016. An explosion at the U.S. airfield early Saturday killed four people, the head of international forces in the country said. (AP Photos/Massoud Hossaini)  (The Associated Press)

  • Afghanistan's National Army soldiers guard, blocking the main road to the Bagram Airfield's main gate in Bagram, north of Kabul, Afghanistan, Saturday, Nov. 12, 2016. An explosion at the U.S. airfield in Afghanistan early Saturday killed four people, the head of international forces in the country said. (AP Photos/Massoud Hossaini)

    Afghanistan's National Army soldiers guard, blocking the main road to the Bagram Airfield's main gate in Bagram, north of Kabul, Afghanistan, Saturday, Nov. 12, 2016. An explosion at the U.S. airfield in Afghanistan early Saturday killed four people, the head of international forces in the country said. (AP Photos/Massoud Hossaini)  (The Associated Press)

NATO says an explosion inside Bagram Airfield, a large U.S. base north of Kabul, has caused casualties.

The statement issued by Operation Resolute Support says the blast happened early Saturday and that "force protection and medical teams are responding to the situation," without providing further details.

The Taliban have fired rockets at Bagram in the past. Afghan officials confirm reports of the explosion but could not provide further details because they do not have access to the base.