Killing of NATO forces in the hands of their Afghan counterpart – a trend termed as 'green on blue attacks' – is a big present and expected future problem. Although certain measures by ISAF and Afghan military authorities have been taken to prevent such killings, the attacks have been reoccurring at short intervals widening the trust gap between Afghans and foreign combatants and damaging their mutual trust.

Once again, on Saturday, two members of Afghan National Police (ANP) opened fire at British servicemen in Lashkargah of Helmand province and killed two of them. While trying to enter Taliban's zone in the province, one of the convicts was shot dead and the other succeeded to flee.

This is a clear indication of the fact that they were sympathizers of Taliban who have been claiming to have infiltrated Afghan army and police ranks. Such incidents that now occur quite frequently seem to have multiplied concerns among NATO and Afghan authorities.

Afghanistan is only two and a half years away from complete withdrawal of US led troops from this country. And this is the time when Afghan security forces should undergo intensive training because they will be responsible for defending Afghanistan against insurgents after 2014.

However, it seems like the green on blue attacks are hampering the pace of crucial military trainings for Afghan security forces. It is quite clear that trainings cannot go ahead smoothly in an environment of fear and mistrust. As Afghanistan will move ahead, incidents of green on blue attacks might be intensified further which will definitely overshadow the transition and withdrawal process.

The attacks also escalate concerns over post-2014 security and stability of Afghanistan as no one can say with confidence that the Taliban would not be able to further infiltrate and influence members of Afghan national army and police.

Once the Taliban started gaining more sympathizers inside military and police forces of Afghanistan, their return to power would be inevitable. Green on blue attacks can be counted as one of the most dangerous tactics of insurgents. Regretfully, NATO and Afghan government have failed to prevent such attacks.