US Defense Secretary Ash Carter has arrived in Afghanistan for a pre-Christmas visit to American troops. This is the fourth visit of the Pentagon chief to Afghanistan since assuming office.

The outgoing U.S. Defense Secretary Ashton Carter made an unannounced visit to Afghanistan part of what was pitched by the Pentagon's worldwide tour of the US troops around the world. However it seen here as a attempt to shored up confidence in Afghanistan's ongoing commitment to the country after more than 15 years. The US has committed $5 billion in defense to Afghanistan until 2020 and Mr Carter thought to re ensure Afghanistan and the president that the support would continue.