Pakistan's military has warned Donald Trump's new generals that they face a "total mess" in Afghanistan unless America and Britain can halt the advance of Isil and the Taliban.

In an interview with the Telegraph, a senior Pakistani army source said the collapse in security since the draw-down of Western troops from Afghanistan meant the West now faced "losing control".

If Islamic State of Iraq and the Levant (Isil) and the Taliban continued to gain strength, he added, it could tempt Russia to stage a Syrian-style intervention, this time on the pretext of protecting its "backyard" in Central Asia.

The source's comments will add to growing concern in Washington and London about the reversal of the hard-won gains made by coalition troops during 16-year-long Afghan campaign.