An Afghan soldier who shot dead a NATO soldier and injured several others last week has fled a military jail with the help of the officer in charge of prison security, Afghan and NATO officials said.

The security chief claimed the man was ill and needed to visit a hospital, and once the detainee’s shackles were off the pair escaped. They are believed to have headed towards the eastern mountain provinces, full of lawless pockets where insurgents hold sway.

The incident in Kandahar is the latest blow to western efforts to train Afghanistan’s patchy and fast-growing army and police before the departure of all foreign combat troops next year. Last year a spate of insider attacks claimed around 60 lives and severely strained relations between Afghan troops and coalition forces working on the training mission. The toll is down to nine so far this year after better vetting of Afghan recruits. — © Guardian Newspapers Limited, 2013