Heightened security is being imposed in Khost and Kandahar in Afghanistan after two Taliban attacks took the lives of 13 Westerners including eight CIA operatives.

A suicide bomber dressed as an Afghan army officer killed the CIA agents who were acting as advisers. The killings have cast doubt on the strategy of mentoring Afghan nationals.

Christine Fair a Georgetown University political analyst said: “They have really become a vehicle of infiltration for the Taliban. This is most certainly a vulnerability in our strategy going forward in trying to hand over security to the Aghans if we don’t really have a way of figuring out who we can trust.”

The attack took place at a fortified combat base near the Pakistan border in Khost province.

In a separate attack in Kandahar, four Canadian soldiers and a journalist were killed when their armoured vehicle was hit by a roadside bomb.

Thirty-four-year-old Michelle Lang was on her first assignment in Afghanistan covering reconstruction projects undertaken by Canadian troops.

And latest reports from Kapisa province, north east of Kabul say two French journalists have been kidnapped along with their Afghan driver and interpreter.

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